I agree that siezing from the starter turning is hard to believe. Im not sure if you have tried all this stuff yet, but here is what I would do in order:

1) Pull starter and try to hand turn it. Makes sense to me the starter that was spinning at the time of failure is most likey to blame.

2) Disconnect all the belt driven accesories and try it.

3) Loosen all the valves as far as you can. See if that lets you turn the engine a bit further than before. If so, then your thought about cam timing being a problem is true. Best way to fix would be to pull the tensioner, remove the front sprocket and re cam time using the cam tower notch. Not exact, but would get your motor spinning again sp you could time it correctly.

4) Pull IP and try it. Since fuel was an issue and it had all those bubba springs on it there could be an internal issue with the IP.

Good Luck!