There aren’t, no. That I know of, anyway. If you’re already using a custom c++ class, why not also create a custom Player State class override OnRep_PlayerName and use it to trigger a BlueprintImplementableEvent on your character?
While blueprint replication events are triggered in bp automatically on the server, you need to manually trigger them yourself on the server if they are defined in c++. Add yourself a SetName (or override the one that’s there) on the server and call it manually after changing the name: