I don't see any problems. I'd like to have the abilities stack a little more-as is, they never get any better. At higher levels, they'll be useless. Maybe breath weapon do 1/2HD, or 'the saem as your tenebrous touch, having phantom cat levels stack'. Poison could be 1d4+1d4/HD, or +1d4/3 Harrowed/Phantom Cat levels. Not so sure about level drain... maybe just +1 per 3... eh. Your call.

...also, being able to combine energy drain and breath weapon would make me a happy kitty. Possibly poison too.