One idea on the tight allen head bolt is to punch a slightly oversize Torx bit in and loosen the whole thing with an air impact wrench, which you probably want done at the local independent shop. Indy is also likely to have lots of special 'easy out' tools to cope with this (not infrequent) problem.

Are you sure there is no chance that you rotated the degree wheel when you did the water pump job? Do you see all the degree wheel markings, similar to those in my picture?

How loose is 'loose' on the cam chain - I assume you mean on the inside of the V on the passenger side, not on the (curved rail) tensioner side? Is the tensioner holding the curved rail up tight against the chain after a few rotations (to charge it with oil/hydraulic pressure)? Did you do anything that might have made the chain jump a cog on the sprocket(s)?