Bush, probably not, given H.W.'s recession. I could see a Hillary presidency, though.
Obama, I'm not sure. Right now he's like 18 or 19 ITTL, and apparently trying to appeal to long legged socialists by reading Marx (assuming his memoirs are accurate to TTL too). Maybe he finds himself as a part of a democratic socialist democratic party? I doubt we would even hear from him until the TL hit the nineties, though.
Trump is definitely a possible candidate, but not for the Republicans. Considering that P_L was talking about reviving the ACU in retcons, I could see his nationalist, populist, and authoritarian approach aligning very well with the ACU. Not so much with the neoliberalism of the Republicans.
But also, butterflies cause hurricanes, and all that.