Honestly, a composting toilet ain’t bad. I have experience with a few composting toilets and the absolute key is making sure the ventilation is tip top shape. That could be installing a decent sized fan to continuously vent it, or making sure the exhaust stack is well into the breeze. It’s the same principle as a chimney.
If you’re not talking about a gas powered incinerator, it’s 1-2kw per poop. And if you poop and your partner poops 20 min later, it restarts the cycle.
With the right battery and inverters and enough generation anything is possible. The thing is that heating and cooling simply is a heavy load. Cooling is easier. If you are at all able, a water source heat pump is much more efficient than air source.