I don't see how him favouring us in the rivalry would mean he isn't signing for them. He wouldn't be the first (for either side).
tbh the only reason I doubt the move is because he's on good money at a recently promoted side so I don't get why he'd take the step down, other than the total value of the contract (i.e. 3x15k vs 1x30k), but if that's the case it will only fuck them really as I doubt he'll be worth that contract in 2 or even 1 years time.
It would be very very strange if he doesn't sign though after all this - as it isn't just rumour talk it is actually people in the club going on about it. Will go down as one of the most desperate PR attempts going.