Reagan would be a likelier candidate as backlash to a progressive Humphrey administration, especially post-Southern Strategy, but I doubt it's Ford even if the climate favored a more moderate Republican. He never really wanted to be president until the job fell in his lap IIRC. Presumably Ford made a name for himself here stopping new progressive legislation in its tracks and then got the co-presidents deal he wanted out of Reagan. As for Wallace, his goal in 1968 was to deny the winner an electoral victory and get 1876 election-style concessions for the South- in which case you would see a third-party to Humphrey's left challenging those concessions in 1972- but for simplicity's sake I'll assume Humphrey won a majority and Wallace went back to trying for the Democrat nomination. Humphrey probably gets the US out of Vietnam early, but it's a pyrrhic victory as the loss is blamed on him. He's a lame duck president without the New Deal Coalition and loses handily.
President Hubert Humphrey (D-MN) / Vice President Edmund Muskie (D-ME)
Congressman Gerald Ford (R-MI) / Governor Ronald Reagan (R-CA) ✓
