You can't say no harm no foul, because having other people do his work is what landed him in this situation.
My issue with all this is first and foremost... there's two sides to every story. I'm not saying Howard is wrong. I'm not saying Stan is wrong. But... there is very little mechanical/technical info here. The claim, "the transmission went up in smoke" could mean anything. There's at least two separate parties involved with working on this vehicle at the time that it went up in smoke.
So after he got screwed with the transmission build, he "located a local transmission builder" and is having yet another unknown do his work for him.
Again not saying either party is wrong, but there's more to it.