Hello Kheka,
The answer to your first question (in my opinion) is yes. I have built my own inventory system utilizing UObject, however there is a caveat to that. As it stands Actors are the only things that do network replication, base UObjects can only be replicated FROM an actor (even though actors are UObjects, Actors are the first in the class hierarchy to implement network replication), UActorComponents support replication but still utilize the owning actor for network replication. So if your game is single player you have nothing to worry about, however if your game is multi-player (like mine) then figuring out replication will be a royal pain as I have found the documentation is severely lacking on the C++ side.
Your second question was answered by cmartel and I cannot answer it any better than he/she 