Stupid pre-buy questions

After you remove the manifolds and clean up the gasket surfaces, use a straight edge to see if there is any warpage or unevenness. If there is, then you can take them to a machine shop to have them machined flat. Use a good quality gasket and make sure you don't over torque the nuts!
As for the transmission leak, (it is a common one BTW), you can replace the seal after the shaft and surfaces are cleaned up. It's kind of a PITA to remove and install while in the car, but it can be done. Your linkage should be just fine if it's factory and complete.
Do yourself a favor and get a factory service manual now before you go any further. The money you spend on it now will be paid back tenfold on just what you will save in time and headaches........
Good luck, and let us know how it goes!