Rob, transom work for either drive answer is yes. B1 same upper as a TRS? - no. Your question Bravo verses TRS has been debated a zillion times here in last few years, I say like most choose B1 ( remember TRS needs a trans also). Speed diff? I doubt. Panther good performance boat? Its a heavy 30ft boat so it'll do a good job crushing waves but I wouldn't spend a lot trying for speed(I had a Formula 311, similar story) Will Alphas hold up for a season? yes going very slow. Hammering the sticks out of the hole would almost destoy them though. No idea on the cost of conversion, I'd guess $5k with used drives. I'll assume the person that told you the boat was excellent per a "marine expert" has a vested interest in the sale - its hard to imagine an 86 without something notably wrong.
Now my qualifications - I am a salesman not a mechanic, just a guy that breaks everything I own so I'm experienced (just wait til you see the bill to rebuild a blown B1

) sold my 311 last year and always looking for a good deal and my gut feeling would be to pass on a boat that old that needs undetermined amount of $ to make the way you want. Slowoutboard's friends boat is a good indicator (slowoutboard its a 30 not a 38!

) of whats out there for the $. Call his buddy and offer him 10k per a good survey (do not buy an old boat without one!!!), the distance would no longer be a hindrance, you could have delivered.
Consider what you'd spend on this prospective boat + transom glass work + cost of Bravos (not cheap!) = a lot more than you'd ever get back for it the next day. Pass on it unless less than 10k.
Just remember opinions, asses and elbows - we all have em!
Good boat hunting...