For someone who is "very new" to mechanics, you know quite a bit!
If your motor mounts are visibly bad, then a good starting point is to replace them and then reassess the rough idle. It's a common topic on this forum, and many of us have had poor luck with aftermarket mounts. So, the conventional wisdom is to save yourself some frustration and buy the expensive Ford parts - at least for the passenger side (hydraulic, ~$125) and the driver's side (tranny mount, ~$75 for my ATX); less expensive from Tousley Ford in MN. If you've worked on the car before, then it's not a horrible job for a do-it-yourselfer. If you search the archive, you'll find plenty of tips.
BTW, if a pulley is rubbing on another piece of metal, then there should be telltale wear marks as well as localized heating, on both parts; test on a cold engine with the engine off so that you don't burn/lose a good finger. I'm not sure what the normal clearance is between the parts on a ZTS; if you have a digital camera with a "macro" focusing feature, then you could post of photo of it.
As far as the radiator cap: mine was also hissing and sometimes leaking coolant. Turns out it was over-torqued (plastic thread fatigue). Try unscrewing it (careful!!) about 10-30 degrees and see if that helps.
"I'm jealous of girls because they get to wear dresses." (Todd Flanders)