Humphrey, Powell, and Dem. Reagan. Then I voted Long and MacArthur because it would be interesting to see the clash of their policies. Also, the Kennedys are overrated and appear way too often in TLs.
I admit I haven't read this TL in its entirety, but how about you make someone President that's not a politician in RL? I've always been partial to the idea of a President Frank Sinatra myself. With the butterfly effect, different people who we've never dreamed of would get into politics, and politicians we know would probably have pursued different careers.