For Banthalos, though it's not a Raven, Huginn or Munnin might work, as they were Odin's two Ravens, his eyes and ears in the world of Midgard. Their names meant "Thought" and "Mind" respectively, which I feel would be fitting enough for an Owl.
Not sure with Ankha. I'm not much of a cat guy, so unless you have some personality already in mind for him/her, or I'm completely forgetting about some god/goddess that demanded someone completely disrobe before they'd trust them, there's not much I can help with there

Edit: If it weren't for Zeus' obvious connection with lightning, and thus appropriateness as a name for some later pet that is lightning related, I'd suggest that for Ankha, as he seemed to be pretty good at getting everyone to drop their pants.
