You should use a Rep_notify based system for the changes.
Changes to the Pawns skeletal mesh should happen on the Owning client first, then RPC the server to update. The server in turn calls a multicast → Sets Rep_Notify variable (preferably a struct).
The OnRep function Needs to exclude the Autonomous local client from executing. You should use Local and Network Roles for flow control. Only the SERVER and Simulated Proxies should execute the rep function update process.
The only other thing I can suggest off the top of my head is to Flush Net Dormancy. This forces dormant actor to replicate but doesn’t change NetDormancy state.
When the new pawn spawns it doesn’t currently have all the updates (replicated vars etc) from all “relevant” actors. Flushing forces a rebroadcast which will update the new guy.