also incompatible with https://github.com/rebane2001/livemessage

That mod is using an old version of Mixin. It needs to update to at least 0.8 to work with the ReplayMod.
If the mod doesn't actually depend on the old version of Mixin, you may be able to work around the issue by renaming either jar file is such a way as to change the order in which they're being loaded (e.g. rename replaymod-1.12.2-2.5.1.jar to aaareplaymod-1.12.2-2.5.1.jar)