I'd look for another one.
The a-arm problem sounds like it has not been well-maintaned. The approach to fixing things sounds like there could be more surprises.
I'd check the receipts on that motor and transmission. If they check out and you want the parts the price might be fair, but based on how he has dealt with other things I'd pass.
Well okay, I'd drag it home as a parts truck if it were free.
