>>27434472Connected isn't completely ridiculous, as long as it's handled right.
If you took the leaf theme far enough they could easily be two parts of a single plant.
Hair's the most obvious location I can think of, but I'm sure it could be worked into any other place. Maybe a shared tail, if it needs to be lower?
That only falls apart at the basic stage being pure fire. So either plant parts would have to be charcoal, or maybe the bodies would be directly in contact...
If you want an extra gimmick, while it might take away from the goal, a gender difference on the final stage where one evolves and the other stays in its second stage might be neat.