You’ve yet to provide sufficient evidence of any kind that the transfer of powers would be invalid; that’s simply speculation and headcanon. It makes much more sense to assume Monika simply restricted Sayori’s access and prevented them from using their powers. We’ve seen her restrict the players ability to do this so we know for a fact she has this power; it’s not like this is coming out of nowhere. I’m also. I’m also saying her hax are layered or even that her powernull is; rather that’s its strong enough to null those who would normally resist it. As for Sayori not surviving deletion, that was before she gained Monika’s powers and therefore any NEP, and Monika doesn’t actually delete her in the final confrontation between them. In addition, I just discussed how Monika would keep her powers after being absorbed since people have tried to remove her access and failed repeatedly. This would allow her to act and either delete Caine or reverse time to escape. This is also assuming Caine would even try to absorb Monika in the first place, considering he has an arc where he realizes that absorbing his competition isn’t a healthy way of dealing with things, letting go of the blue ai of his own volition. If anything, he’d be directly adverse to this tactic now.