Pix would be helpful, but I'll take a couple guesses.
2.5" diameter cover - Might be part of the ADD vacuum acutator cover. Wire is probably part of the ADD system, as well.
I get at my V6 oil filter by going in from the bottom/front of the engine -- kinda near the radiator support. One trick I use, is to NOT tighten the filter on super-tight, by hand. As long as it doesn't leak after you change it, it WILL get tighter with heat and use.
CV's are not that difficult to change. There is a 1993 FSM stickied at the top of this forum. You can search there and get the straight dope. When you get your new boot in place, use some silicone spray on the outside every oil change (not WD-40). That will help the CV boot live longer. ( In fact, use it on all the rubber boots / seals / body insulators.)
My guess on the 'little switch south of the shifters' is that it's likely your ECT Power/Normal switch. Pressed IN, it holds the auto tranny in Low and 2nd gear longer before shifting up, letting the engine wind to a higher RPM. I find it aids in around-town driveabiltiy. I ususally keep my O/D Off (switch on the shifter) and the ECT ON , when I'm in town and below 50 mph.
There's lots on here and other boards about rear sag. I think most owners just leave it, if it's not 'too' bad ( 1" or less). It's a pretty easy swap to get some OME coils and restore the ride height. If you want a little more than stock height, get the OME HD coils. Then you can put some Ball Joint spacers on the front -- get about 1.5" lift up there and fit some 33" tires all around.
Incidentally, 33" is about as big as you might want to go, if your stock tire size was P225's. You likely have 4.56 gears and the V6 / auto tranny combo kinda starts dogging around with too tall of a tire.
BTW -- Glad to have ya,, and welcome to the board. <img src="/forums/images/graemlins/cheers.gif" alt="" />
Mike in AR