what kind of work does a new oil pump and a rear main seal entail, and how much can i expect to be charged at your average garage? 86 GT (2.8 auto)

Unfortunately just the word Fiero causes most garages to double the price, mostly due to thier ignorance of the car. Both jobs require oil pan removal, which can be done without pulling the motor. Oil pump is easy to just swap, rear main can get a little involved but not too difficult just got to pat attention and dont mess up any bearings.

ive got a shop here near me thats amazing, their $ per hour is a tad high, but they never overcharge. i had em re-do part of my quads wiring harness (original owner installed a bit messy) and they were VERY reasonable.

so neither of these repairs are extreme or time/cost consuming? this is my main concern as i've yet to consult the shop.

No, should be pretty basic for an equipped shop with a lift.

The shop may want to pull the motor/trans to install a new rear seal.