It depends on his opponents, not only era. Many fighters had great records in great eras because they ducked the best competition. Holmes wouldn't probably go 48-0 in the late 60s and early 70s if he had faced Frazier, Ali, Foreman, Norton and others. Not likely in the 1930s either with Joe Louis and some active dangerous opponents in Baer, Schmeling, Braddock, Farr, Sharkey and others though with beating Louis the chances are much more likely. Definitely not in the 1890s because back then the best fighters fought against each other multiple times.
From the limited footage I have seen of the era, I honestly feel that the Holmes of the 1980s could have gone 148-0 in the 1890s. With the evolution of the sport in the interim 90 years which Larry benefitted from, I honestly feel he would have toyed with the other top fighters. Had Larry been around in the 1890s with access to the same training and knowledge of the sport that existed at that time, maybe it would have been different but I have taken this to mean the exact same version of Holmes that we saw. I only see Louis possibly beating him in the 30s and Joe would have had huge problems with Larry's movement. I just don't see Larry struggling with the other names you mention. Maybe Baer but he'd need to land an almighty shot because he doesn't outbox Holmes and Larry proved himself capable of surviving and coming back strongly from massive shots on several occasions. I think the 70s would have been tricky as would the 60s with Liston, Ali and young Frazier. Also had his 7 year reign been from 1986-93 it would have meant running the gauntlet of prime Tyson, Holyfield and Bowe as well as the green but dangerous version of Lewis. Anyone would do well to come through that without a blemish on their record.
From 1985-2000 He'd have to fight Bowe, Lewis, Tyson (prime), Holyfield and loads of contenders that would be among his best wins.
I think Holmes beats 70s Ali, Joe Louis (any) and Marciano. I think he biggest worries are Wlad, Liston, 60s Ali Lennox, Frazier and Foreman.
If you assume that he wouldn't change his style at all, then with smaller gloves he would injury his hands after less than 20 fights and would never be the same. I also don't know how he'd fare against more grappling and longer distances. Not to mention the racism that would hurt him a lot in that period. I'm not sure he would accomplish much more than Peter Jackson, it's possible but far from likely.
