Welcome to the forum!! Feel free to post some pictures of your car, everyone loves to see Fiero pictures
For the engine temp, stock setting is 220-235 operating temperature. Its pretty high off the get-go. If yours is running higher than that, then there could be a problem. Like mentioned above it could also just be the gauge is off. But also could be low coolant, bent or crushed metal line under the car restricting flow, broken thermostat, bad fan switch, relay or fuse, leaking radiator cap or thermostat cap. What temp is it running at? Does it ever get into the danger zone?
For common problems, well there's a myriad of possibilities, but no guarantee that you will experience any of them. Personally, I have had to replace the fan switch on all of my Fieros because it would not actuate the fan anymore. I always replace it with Rodney's low temp switch. I would highly recommend Rodney's low temp fan switch. It will keep the car running at a lot more comfortable temp range. Get it here: http://rodneydickman.com/ca...th=69&products_id=88
For cars that have sat a lot, fuel pump, brake lines, water pump and clutch slave cylinder seem to be the first to stop working, or not work to start with. Sounds like your car is already all working though, so that's a plus. If it was driven regularly by previous owners, then those are not as likely since rubbers and seals are more likely to dry out, get brittle and crack when they sit unused.
Another common one is headlights stop working. It can be caused by bad relays or stripped plastic gears. If yours are working now, then you probably don't need to worry about it at the moment. But it could be a good preemptive step to rebuild the headlight motors and replace the gears. Fiero store has rebuild kits, motors, relays (https://www.fierostore.com/Product/Browse.aspx?d=273&p=1) as does Rodney with metal gears or his relay upgrade kit (http://rodneydickman.com/catalog/index.php?cPath=32).
Other possibilities are vacuum leak due to cracked vacuum line or connector. You will probably get a check engine light if that happens. Also a cracked EGR tube is very common on the v6. Look for high idle. If the car idles over 1000, then there could be a small crack. I've seen it up to 2500 at idle for a large crack in the EGR tube. Its easy to replace and again the Fiero Store and Rodney both have them. They aren't cheap for being a tube, I believe Rodney's are cheaper. I've also made my own before from a flexible metal propane gas line.