I really like some of the ideas. The Bernard option is great, who can say no to a killing machine in the group? Also, I really like Eberron setting. I hope someday we have a game set on Shar ^_^
Omellum would certainly be something. Although to follow on the logic, you would also need a gnoll to have some use for the rest of the flesh. hahaha
And the owlbear or any other pet is always a winner. I love the dog in shadowrun game. Or any other game that allows you to have a dog as a companion. And there was that spirit bear in neverwinter that also was quite fun to have around.
And Lia really seem to have potential to become a companion. Which class do you think she has?
As for Halsin being overpowered, mechanic wise, doesn't have to be. After all, he was captured by goblins and we do already have companions with epic background but still start at level 1. So it is just a matter to make him the same level as your character. No big deal.