Who you rescue at the end of the Presidio quest (Quid Pro Quo) depends on how your parents were orphaned, not your class (who you acquire at the beginning of the Gunn's gold quest depends on your class). Lucky Jack Russel is who you receive if your parents were shipwrecked. The other options are:
The Guinea pig Gaspard de Vole (Armada) The rat Milo Graytail (storm) The crab Birgus Latro (giant squid) The zombie human Dead Mike (mutiny)
I wonder if, at some point in the future, we will receive different companions depending on where we were raised.
I had choose intentionally a Jack Russell as a companion for my buccaneer, this because it has nice resistances so i use him as a wall vs ranged/swashbuckler/witchdoctor units and he does some more damage vs them since it is a privateer yes but unlike most of other privateer companions he is strength based! Means that he can take profit very well from strength buffs, Jack does his duty very well .