1) no, you need an upper cam mount from the Z6 (I have one for sale)
2) If the EX tranny is a manual and your old motor was a manual, it will all work fine.
3) Yes, you will need a hoist.
4) You will need to use heat resistant paint. AZ or some auto store sells paint specifically for this, but you have to prep the surface VERY well to get them to work correctly.
5) Depends on what you're going to do to the motor. If you're going to boost it with a good deal of pressure then it would be a good idea to build up the internals with some rods and pistons. You could change your compression at this point too.
6) Yes, everything is the same.