<Suggestion>About Ice-and-Fire
Why not make one mod that can play with LOTR mod in 1.7.10? 1.7.10 ALSO has A LOT OF PLAYERS! I hope you think my advice is useful
LOTR mod has a 1.16.5 version, for which i am developing a modpack which is currently re-adding all of the structures from the 1.7.10 version, but with a new look and better loot. it has a magic system based on learning elvish or morgul words of power, as well as an obscure ringforging mechanic, all of which you will have to test out for yourself. it is yet unreleased, but you can watch for it's release by following my curseforge page https://www.curseforge.com/members/sound_of_silence221/projects
Custom dragons spawn in the north of the map in Forodowaith, with custom names, health pools, and drops
Seeing as there will never be a backport of Ice and Fire, but there are and continue to be forward-ports of the LOTR mod, this is your best option.