> og var ekki manna (gen pl) við fyrst nema Kolskeggur.

"no one", lit. "nothing of men". For the use of the neuter with the
genitive plural, compare 'hvat manna'.

'ok er ekki manna frá honum komit' (Landnámabók).
'Þeir sá ekki manna úti' (Þorvalds þáttr tasalda).
'Þeir sá ok ekki manna í höllinni' (Geirmundar þáttr heljarskins).
'Hundr hans var hjá honum en ekki manna' (Bárðar saga Snæfelsáss).
'Ok er þeir kómu að eyjunni sá þeir ekki manna úti á boenum ok ekki
úti á eyjunni' (Færeyjinga saga).

> "Vel er slíkt boðið (isn´t this pp rather than noun?),"
> Such is well offered

Yes, I think so.

> þeim mun mjög mislíka.
> (it) will greatly displease them.

Yes, or you could translate it "they will be much displeased". The
verb 'mislíka' is used with a dative experiencer, like 'líka',
'þykkja'. I think this is what would be called 'raising' in modern
linguitical jargon [ http://en.wikipedia.org/wiki/Raising ]. The
dative experiencer (according to some linguists: the subject) of
'mislíka' has been 'raised' from the infinitive clause to become the
syntactic subject of the auxiliary 'mun', although it still derives
its semantic role, and its case, from the lexical verb 'mislíka'. See
Faarlund: Old Norse Syntax 9.3.2, p. 204-210.

> Vilt þú nokkuð sonu þína við láta (?) vera?

"have your sons present" = láta sonu þína vera við

'láta' "cause to"
'vera' "be"
'við' "present"

> Svo munum vér þá gera,

I think: 'svo' "thus" = as you have asked.

LN