cost probably too much if you're asking us if you got a good deal, haha. it's not a bad deal and not a good one, IMO. i actually prefer 20longs to 29's and would never own a 29 again.
if i were you, i would give your friend an ultimatum on the pacu. if he can't take it back in a short amount of time, take it to your LFS for some credit or something.
hope you get that 125 set up pretty quickly, but, IMO, you should be okay for a little while as long as you keep up on the water changes.