> (ie your desire to blame someone is excusable/understandable)

Schools' Edition notes: LEITA Á NOKKUR: leita fyrir sér (um bætur)
einhvers staðar. NOKKUR er hér ao. "to seek (compensation) for oneself
somewhere. `nokkur' is an adverb here." See the Proverbs page [
http://www.usask.ca/english/icelanders/proverbs_BNS.html ], which is
always worth checking; the German explanation says: `nökkur' not
feminine agreeing with `várkunn', but adverbial "somewhere" [...] from
`ne-veitk-hvar' "I know not where" (the pronoun is a contraction of
`ne veitk hverr' "I know not who"). MM & HP: "You cannot be blamed
for seeking compensation somewhere."

Náið er, bróðir, nef augum.
"The nose is near the eyes, brother," i.e. "what involves those close
to us involves us as well." [
http://www.usask.ca/english/icelanders/proverbs_BNS.html ].

Schools' Edition: DREPA NIÐUR ILLU ORÐI: þagga niður illt umtal.
"silence gossip / stop bad things from being said."

rífka svo ráð fyrir dóttur þinni
MM & HP "In that way we can improve your daughter's prospects." That
is, her marriage prospects. Schools' Edition notes: RÍFKA RÁÐ: bæta ráð.

Er sá einn til að þetta orðtak falli niður sem skjótast því að þá er
betur að hér sé til talað.
`sá' is the masculine singular demonstrative pronoun, agreeing with
`einn'. `vera til' "to be, to exist." `Er sá einn til' "There is
only one [option]", i.e. "we only have one choice / course of action
available to us." MM & HP: "Our only course is to settle this claim
now, and the less said about it, the better." Schools' Edition notes:
ER SÁ EINN TIL: aðeins er um eitt að ræða. Orðið KOSTUR er
undanskilið. "There's only one thing to be discussed. The word
`option' is understood."

> arbitrate in the case

That's right. Schools' Edition notes: GERA UM MÁLIÐ: dæma, úrskurða,
meta málið. "to judge, decide, arbitrate, make an assessment in the case."

Síðan gerði Hrútur og mælti (simply did or arbitrated in this context?)
Arbitrated. MM & HP: "Then Hrut made his assessment and announced."

Schools' Edition: LÚKA UPP GERÐINNI: kveða upp úrskurð. "Pronounce the
verdict / announce the decision."

Schools' Edition: TVÖ HUNDRUÐ SILFURS ... MANNGJÖLD: vanaleg manngjöld
voru eitt hundrað silfurs og var það greitt fyrir Atla og Brynjólf
rósta (77 og 79). Hins vegar eru manngjöld einatt í sögunni tvö
hundruð silfurs (85, 199 og 243). "The usual compensation for a
killing was one hundred ounces of silver; this is what was paid for
Atli and Brynjolf the Unruly. On the other hand, wergilds in the saga
are often two hundred ounces of silver."

Schools' Edition: SKIKKJA: yfirhöfn, ermalaus og bundin saman yfir
bringuna. "Mantle, sleeveless and fastened over the breast."

og undi nú vel við þar sem komið var of fór heim
MM & HP: "and went home well pleased with the outcome." If I've
understood correctly, `við' here means "with", he was well contented,
very happy with... `þar sem komið var' is the complement of `við'.
This whole clause, `þar sem komið var' is what he was happy with.
`þar', on its own = "there", but `þar sem' (`þar' + the relative
particle `sem') = "where". Literally, he was pleased with "where it
had come to." That is, "the outcome", "what had come of his visit",
"where matters stood after what had transpired."

Hallgerður beiddi Höskuld að Þjóstólfur skyldi fara heim.
MM & HP: "Hallgerd asked Hoskuld to take Thjostolf into his household."

Schools' Edition: FÉ HALLGERÐAR GEKK FRAM: fé Hallgerðar óx. "H.'s
wealth increased."