Not that it matters greatly in the scheme of things (since I agree mostly with what you have put down). However, a slight correction of the record is needed re Mercer, since he did (wisely) take a knee against Holyfield after getting caught with a couple of good left-hooks. The first one had him in a bit of trouble and when the second one landed, Mercer realized he needed a moment. Separately, I also think Morrison has a fair chance against Wilder.
He'd get KOed a lot in the 90's. He might win a belt.. maybe.. WBO was not highly regarded in the 90's, he might win that belt.. but he wouldn't hold onto it very long like he did in his era. I rate him with Primo Carnera.. maybe..