Greetings!

Here are my comments on this LoI (I've focused primarily on armory).

1: Æthelmearc, Kingdom of - The stirrup as drawn is in rather trian
aspect.  Is there evidence of stirrups being drawn like this in period
armory?  (If so, then this rendition should be registerable, rather
like dice being registerable in trian aspect.)

When listed potential conflicts, it's really helpful to include the
date of registration -- I, and a couple of other Laurel staff, have
archive CDs that go up through 1993; if the date of registration is
included, then I can tell at a glance whether I have a copy of the
emblazon, or not.  James's badge was, luckily, registered 1991.
I've put the emblazon at 
http://www.ellipsis.cx/~liana/temp/james-badge.jpg for people to
consider.  In my opinion, the azure parts make up less than half the
tincture, and so this is a conflict.

2: Æthelmearc, Kingdom of - Scrolls are unrolled by default, so 
this can be simplified to "Sable, a scroll bendwise and overall in
saltire a rapier and a sword Or."  This violates the "sword-and-
dagger" precedent which forbids the use of blazonably distinct
charges which are not a CD apart in the same charge group:

"Edward Reinherz. Device. Per chevron rayonny sable and Or two roses 
Or and a rose gules slipped and leaved vert. This is being returned 
for violating what is known as "the sword and dagger rule", using 
two variants of the same charge in the same group. Making all the 
roses slipped and leaved, or none of them slipped and leaved would 
correct this problem." [LoAR 02/1997]

"Helen Hawksworth.  Device change. Per bend sable and gules, in 
bend sinister a hawk trussing a duck and a bird volant bendwise 
sinister argent all within a bordure erminois.  Blazoned on the LoI 
as Per bend sable and gules, in bend sinister a hawk trussing a 
duck and a raven volant bendwise sinister argent all within a 
bordure erminois, the use of two different birds that are not a CD 
apart is cause for return under the "sword-and-dagger" rule."
[LoAR 06/2007]

3: Aíbell ingen Chernacháin - I believe this conflicts with 
Robert FitzAlwyn (reg. 02/1987 via the Middle), "Argent, a 
dragon sejant affronty, wings elevated and displayed, on a 
chief triangular sable a broad arrow gules, enflamed Or,"
with just one CD for the changes to the tertiary.  There is
none for the maintained charge, and I do not think there is a
CD for posture between "sejant affronty wings displayed"
and "displayed".  Robert's arms can be viewed at
http://www.ellipsis.cx/~liana/temp/robert-device.jpg 

4: Benedict Fergus atte Mede - No conflicts found.

6: Brandr húslangr - Unfortunately, the arms also conflict with
Andréa de Champs de Batailles (reg. 11/1979 via the West), "Azure, 
on a bend argent a unicorn's head palewise couped sable between 
two cinquefoils purpure," with one CD for the number and tincture
of the tertiaries, but that's it.

7: Bridget Cordelia of Beau Fleuve - Gorgeous arms!  They're clear of
Nuala níc Ailín (reg. 02/2005 via Caid), "Per pale argent and sable, 
two fleurs-de-lys counterchanged," with one CD for reversing the field
tinctures and another for the number of fleurs.  They're clear of
Siber Throckmorton O'Ciaragain (reg. 12/1994 via Meridies), "Per pale 
sable and argent, a unicorn rampant contourny between three fleur-de-lys 
counterchanged," by X.1.  Those are the closest I found.

8: Ceindrech verch Elidir - For the period that she's interested in,
and the period that the elements are dated from, she needs the Old
Welsh spelling <merch>, not the medieval Welsh spelling <verch>.

9: Erlendr rauðhrafn - Precedent says that bynames of the form
"color + animal" are not registerable in Norse:

"Kristin Hvithestr. This name is being returned for lack of 
documentation that the construction of the byname Hvithestr 
'white horse' follows a period pattern of bynames used in Old 
Norse in period...Lacking solid evidence of a clear pattern of 
descriptive bynames of the form [color] + [animal] in Old Norse, 
there is no support for the submitted Hvithestr as a plausible 
descriptive byname in Old Norse." [LoAR 12/2003]

The example of <rauðrefr> in Geirr Bassi is an error; the byname
actually found in the sagas is <rauðnefr> 'red nose'.

The examples of the given names would support <Rauðhrafn> as a
given name, so <Erlendr Rauðhrafns son> would be registerable,
but would not have the meaning that he desires.  On the other
hand, Geirr Bassi has <Hrafna-> as a prepended given name.  He
could be <Hrafna-Erlendr rauðr> 'raven-Erlendr red' or 
<Hrafna Erlendr inn rauði> 'raven-Erlender the red', since precedent
says that double descriptive bynames are registerable in Old Norse,
so long as both could be used to describe the same person as the
same point in his life:

"Submitted as Svein Sutari Svithanda, the name contains two descriptive 
bynames, a practice that is very rare in Old Norse names. However, Golden 
Pillar notes the following precedent:
    This name contains two non-patronymic bynames in Norse, which has 
previously been cause for return. Gunnvör silfrahárr (formerly Gunnora 
Hallakarva) found examples of people who were referred to using two non-
patronymic bynames simultaneously. She provided the following examples and 
translations so each name may be viewed in context:
        (1) Þórsteinn surts inn spaka (Thórsteinn Black the Wise) - Laxdæla 
saga (c. 1245), ch. 6. Ósk hét hin fjórða dóttir Þórsteins rauðs. Hún var 
móðir Þorsteins surts hins spaka er fann sumarauka. [Ósk was the name of 
the fourth daughter of Þórsteinn rauðr. She was the mother of Þórsteinn 
surts inn spaka, who found the "Summer eke".]
        (2) Ari prests hins fróði (Ari the priest the wise) - Landnámabók 
ch. 83. Þórsteinn Hallsson var faðir Gyðríðar, móður Jóreiðar, móður Ara 
prests hins fróða. [Þórsteinn Hallsson was the father of Gyðríðr, who was 
the mother of Jóreiðr, who was the mother of Ari prests hins fróða.]
        (3) Þórolfr Mostrarskeggr - Eyrbyggja saga ch. 3 (prepended and 
appended by-names) Hrólfr var höfðingi mikill og hinn mesti rausnarmaður. 
Hann varðveitti þar í eyjunni Þórshof og var mikill vinur Þórs og af því 
var hann Þórólfr kallaður. Hann var mikill maður og sterkur, fríður sýnum 
og hafði skegg mikið. Því var hann kallaður Mostrarskegg. [Hrólfr was a 
mighty chief, and a man of the greatest largesse. He had the ward of 
Thór's temple there in the island, and was a great friend of Thór, and 
therefore he was called Þórolfr. He was a big man and a strong, fair to 
look on, and had a great beard; therefore was he called Mostrarskeggr, and 
he was the noblest man in the island.
    Given these examples, a name using two non-patronymic bynames in Old 
Norse is registerable so long as the bynames could reasonably be used to 
simultaneously describe the same person. In the case of the submitted name, 
the two bynames mean 'shrieking' and 'woman from the Orkney Islands'. These 
bynames have different meanings and could both have described the same 
person at the same point in her life. Therefore, this name is 
registerable. [Þórdís gjallandi eyverska, 05/02, A-Outlands]

"Precedent requires that descriptive bynames in Old Norse be transcribed 
in all lowercase. Therefore, we have changed the name to Svein sutari 
svithanda; the name means "Svein the tanner, earthscorcher." [Svein sutari 
svithanda, LoAR 11/2004, Calontir-A]"

Both <rauðr> and <inn rauði> can be found in Geirr Bassi, the latter being
much the commoner.

The indented line here is drawn in the "pinking shears" style; this is
not registerable:

"Niccolo Talenti.  Device. Per pale sable and vert, three triangles one 
and two, on a chief indented Or a crescent sable. This device is returned 
for redraw; the line of division has far too many shallow indents, 
creating a "pinking shears" effect. This has long been grounds for return. 
On resubmission, please advise the submitter to use about half as many 
indents, each about twice as deep. The chief should also be drawn somewhat 
wider." [LoAR 08/2006]

10: Finnr jafnkollr - No conflicts found with the arms.

14: Maghnus an Chnoic na n'Iora - As drawn, this is "Azure, a chevron
and in base a single-headed chess knight argent", not two co-primaries.
No conflicts found.

When was his name registered?

15: Meadhbh of Clan McBain of Harlaw - Since there is no CD between
dovetailed and embattled, this conflicts with Ursula von Liste (reg.
05/1984 via the Middle), "Azure, ermined argent, a gryphon segreant 
queue-forchee within a bordure embattled Or".

Precedent says:

"The only documentation provided for Claymore in the LoI was:
        Claymore comes from Deaton Claymore, the head of the household 
with whom the lady is affiliated; His Grace has provided a letter of 
permission to use that element of his registered name.

"Unless the submitter is an immediate family member (and that's legal 
family member, not SCA household family) the Grandfather Clause is 
inapplicable. As no documentation has been provided for such a 
relationship, there was no usable documentation provided for Claymore."
 [Renee Claymore, 11/2002, A-Æthelmearc]

"Regarding the byname de Battenhelm, the LoI stated:
        while the client would prefer "du" Battenhelm, "du" is basically 
a French abbreviation and Battenhelm is not French. There have been 
three registrations of "de" Battenhelm to members of the household the 
client belongs to. These are: Margarite Isabeau de Battenhelm 8/83, 
Erlichin de Battenhelm 7/84 and Frances de Battenhelm 7/84. As he belongs 
to this household, he wishes to use their byname.

"Name elements are only grandfathered to members of a person's immediate 
family (parent, sibling, child, spouse). These relationships are limited 
to legal relationships, not household "family" relationships. As no 
documentation has been provided that the submitter is legally related to 
Margarite, Erlichin, or Frances, he cannot claim use of de Battenhelm via 
the Grandfather Clause. As no documentation has been provided and none was 
found that any form of Battenhelm is a plausible period byname, it is not 
registerable." [Alcyoneus de Battenhelm, 04/2002, R-Calontir]

And:

"Dùghall Bàn of Clann Mhuirich.  Name.
    Bynames of the type of Clan X, not found in period, have been 
disallowed since late 1998. We would therefore dropped that element; 
however, as he allows no major changes we have to return this."

"Metylda of Clann Mhuirich. Name.
    Bynames of the type of Clan X have been disallowed since late 
1998. As she allows no major changes we have to return the name."

Both from 06/2000.

I found no conflicts with <Meadhbh MacBane>; Black s.n. MacBean
has <M'Bane> 1513, and per the 09/2007 LoAR, <M'> is a scribal
abbreviation which would expand to <Mac->.

17: Robert l'Etourdi - "vert" should not be capitalized in the
blazon.

-Aryanhwy, Albion