I agree with you that it looks very demasoni-esque, as I have one. Though his body shape may be a bit different.From looking at plenty of pictures I would think it is definitely a hybrid. It looks mostly DemasonI to me but not quite all there.
The reason I thought it may be a KenyI female is that I have a KenyI male (also may be a hybrid) and he is the tank boss. This blue fish is allowed to hang out in the Kenyi’s Area while all other fish are chased away.
With that said, I have not seen any spawning activity between them.
The more I dig into it, the more I feel like all of my fish are hybrids.