> var vænn að yfirliti og ljóslitaður (P), rétt nefið og hafið (G,

noun,I belive but definitely not hafa) upp í framanvert (P),

> was beautiful in appearance and fair-complexioned, the nose straight

and the lifting (upturn?) up on (the) foremost (bit, ie the tip) (ie
slightly upturned?),

MM & HP "slightly tilted at the tip". I think 'hafið' = normalised
old spelling 'hafit' (neuter past participle of 'hefja' "to raise").

> hárið mikið, gult, og fór vel

MM & HP: "a fine head of thick flaxen hair." Just for comparison,
here are their translations of the other descriptive terms.

> kurteisastur

MM & HP: "extremely well-bred"

> harðger í öllu

MM & HP: "fearless"

> ráðhollur og góðgjarn
> giving-good-advice and eager-to-do-good (benevolent)

MM & HP seem not to translate these terms, maybe for stylistic reasons?

> mildur og stilltur vel

MM & HP: "generous and even tempered". (Dictionaries have both
definitions for 'mildr', "gentle" and "generous"). 'stilltr' is the
past participle of the verb 'stilla' whose meanings include "to
moderate, to temper", i.e. he was well able to control his own temper.

> drengur góður

MM & HP "courageous"

> og öruggur í öllu

MM & HP: "and reliable"

> Una hins óborna

MM & HP: "of Uni the Illegitimate"

> halti
> (the) limper

Yes; cognate with English 'halt'.