Why do the UObjects needs to be persistent? Where are you storing them, the game instance? game state? If you are using them for simple data storing i.e. health, inventory I would suggest using structs instead you can have them as variables on actors and replicate them.
If I understand your problem correctly you want your actors to replicate data that you are storing inside UObjects external to the actors that use them and this data needs to be level persistent (but not game persistent, as in character progress). I have a question about your game. Is it a multiplayer where characters join a level map but you want to have persistent data when they leave the map? Now if they leave the map, or disconnect then how is the server supposed to know who does the data that it saved belongs to? You would have to create some sort of complicated id logic that only lasts while the server lives. Maybe what you really need is an external database