my WP also had a paper gasket. I just used it without anything else.... perhaps a noob mistake... I don't have many miles on the pump to be able to advise one way or the other.

I think that cable you're worried about might be the positive lead for the battery, follow it to the front of the engine bay to confirm... not sure what you would do to fix it, but some electrical tape, or maybe some other kind of wrapped foam insulation would help.

AC pump is a huge pain....

my timing belt cover also has a piece missing... it isn't quite as big as your gap, but I put some tape over it for the time being... I doubt the tape will last too long, but it will work until I come up with a better solution. The better solution might be just to order a new timing belt cover)