>>Laad snechta an gemrid so sunnrad, co fúair Conall a fástig hé ac fuine
>>a chotach & a ara. Bátar tra na eochu fón carpat amuich.
> I thought 'a ara' might be the preposition 'i' (in) plus a variant
> spelling of
> dative singular of the ia-stem feminine "aire...act of guarding, watching
> tending, caring for".
> I didn't think it could be the word for charioteer (ara/arae) because
> that's a dental stem and Strachan lists 'araid' as the spelling for both
> accusative and dative singular forms.
"ocus a ara" is an afterthought, and as such the "charioteer" is mentioned
in the nominative; something like: "Conall Cernach found Cet cooking his
portion, and his charioteer (was also there)". Since the charioteer is not
an important character as such (I don't know if he will turn into one in
the course of the tale), he can be mentioned in the passing like this.
> tra na eochu -- because 'na eochu' looks like accusative plural of 'ech'
> (horse), I thought 'tra' might be a variant spelling of the preposition
> 'tre' (through).
No. "trá" is the particle "then, thus".