Am buying my first 7.3 just a few ?s

[sbbtmatt]

I am buying a 2002 F350 in the next week or so. It is a really nice truck with only 80k on the clock. It needs a few minor things so I just want to get some advice.

1 The heat is stuck on defrost my mech. said probably vacuum pump. Any thoughts?
2 The mirrors will go up,down and to the left but not right, so the drives will go out but not in and the passenger side will go in but not out. My guess is the mirror adjustment switch, any thoughts?
3 The truck is about due to get all its fluids serviced. The trans is a built Sun Coast with the extra deep pan, the diffs both have the extra size covers. Recommendations on what fluids to use?
4 The ball joints and front drive axle u-joints are getting lose, any after market ones that are better than OEM?
5 It has an after market dual steering stabilizer (sky jacker I believe) it has stock suspension and tires other than that is it worth keeping it? I

It also has stacks and I just ordered a 4inch Stainless turbo back MBRP for it.