Which of these lght heavy s could have replicated spinks in beating holmes?

At that stage in Holmes' career anything is possible. But I don't think Moorer had the ring smarts early on to take advantage of an aging Holmes. The light heavyweight rendition of MM was far too interested in just mowing down weak opponents and that wouldn't work well against a full fledged heavyweight of Larry's skills and durability even at the age of 36.. That and if we look at Moorer's " actual" heavyweight career, he had some flat performances in the beginning and against some mediocre guys ( see everett Martin fight. )

 

If we're talking the Moorer who beat Holy, and even the one who lost to Foreman, I think he has a chance to capitalize on an aging and disinterested Holmes.

 

Perhaps but Moorer was already three to four years into his heavyweight career when he fought those guys. Hardly the same as someone taking the step up for the first time as Spinks did. Even then he still managed to get knocked out by a 45 year old and got decked and narrowly decisioned a horribly prepared Evander.

 

Conn and Greb could do it. I wouldn't favor Archie Moore over any atg heavyweight.

 

Thought he fought Foreman well, though, until he got caught like that.

It's very possible he wasn't ready when he first made the jump, but I didn't interpret the criteria that strictly.

 

It was the worst version of Holmes i ever saw to this point. He was a lot better in the rematch but still obviously way past his best. In the first fight he was ponderous and terribly uninspired.

 

Not on the list, but maybe Dwight Qawi? (Assume we could take him at his best). I think he would have been hard for Holmes if he could close the gap.
Moorer could present some problems, but he would also have been susceptible to a counter right from Holmes, and really I don't think he was that durable, so there would be a chance he could get knocked down a few times and possible TKOd. But I would still give him a good chance.
I know nothing about Harry Greb having no visual evidence, so no comment.
Billy Conn was too small, imo, and the things that troubled Louis would likely not be an issue for Holmes, (he will not be outboxing/jabbing even that version of Holmes)
Someone said RJJ, I think maybe so, that could be very interesting.
I would think the Toney who fought Holyfield/Ruiz could also be an interesting fight.
Note, all of these I am assuming, as the question stated, are at their best, and they are fighting the Holmes who fought Michael Spinks, in fight I. I don't pick them to beat a prime (or even just past prime) Larry.

 

Tunney was a very good boxer mover. Very smart. He could box and move all night. And he was tough. Holmes was older and slower by 1985 and would likely lose the decision.

 

In Holmes autobiography Against the Odds he stated how a injury stopped him from
throwing right hands fully and that was why he was so lifeless and uninspired in first
Spinks fight. The second fight Holmes put in a better effort but so had Spinks because
he had fully adjusted to HW and had improved too.
Based on Holmes first effort against Spinks Jones , Moorer, Walcott , Charles would
have a definite chance of beating Larry as they would be chasing history.