The #1 Contender thing is a bit strange. I think the theory is because Lashley refused to work/tried to quit, he lost the right.
Samoa Joe isn't a #1 contender, he can cash in any time, he could wait months, they can't wait for that.
A lot of these quick turns, like Team 3D are because new stars have come in and they've changed to fit the feuds. Back when they turned heel they hardly knew they'd be fighting Nasty Boys a few months later.
Foley's just Foley, his character is all over the place by nature.