Dafydd |
Welcome to the grey area my friend. While I do not see anything that specifically says you can, I also do not see anything that says you can not.
While Hit Dice are not Character Level, Character Level is Hit Dice. IMO, as long as you can get to the required CHA, I would approve it. However, this is a grey area in the rules, so do not expect every GM to agree with it. There are some inherent problems, thematically, with bloodlines for animals.