So anyone before the late-mid 90s pretty much when weight cutting was not at it's zenith. Foster, Spinks, Qawi? ect
Possibly, assuming they could cut the weight safely. Let's not forget that just because you can make a particular weight doesn't mean that you will be as effective at it. Canelo is the prime example, cutting huge amounts of weight in order to make lower weights. He was notorious for his stamina problems, but the more he moved up in weight the more those stamina problems vanished.
MOST of the Middles cum L-HWs would be Welters cum Middles today... so Most of them. the L-HWs cum HWs then, would be S-MW's cum L-HW's today.
Yeah, loads. Many of the true greats (Moore, Charles, Greb, my top three) were middleweights for a spell and could have remained there indefinitely in a modern setting. These three would box ATG careers without ever seeing 175lbs if they so chose.
