Yea, the problem with the info from the net, is most of it is from retailers. Lot more people have tanks in the 75-100gal range, then over 200 gallons, so that's what the retailer is going to post. A smaller home isn't going to outright kill a fish, but obviously isn't suitable.
I would say a 5" Annularis probably has at least 2 years of growth, before he outsizes a 6' 125gal, especially with only 3 other tankmates. So you wouldn't have to upgrade right away.
Some angels that would permanently fit into a 125gal, Flagfin, Singapore, any angels of a Genicanthus genus (probably could even do a pair of those), Majestic, Cream, Poma, Blue Spotted, and not sure of your budget, but Goldflake, Bandit, Blue Line.