Played a bit more with it and tested on LAN, and it the system does work very well in multiplayer 
I’m running into an issue though, When creating a new inventory item :
1- duplicating a helmet and changing it to ‘mine’ still keeps the same thumbnail of the blueprint actor.
2- I keep trying different settings but my skeletal mesh doesn’t seem to go on the head socket. It’s instead glitching at the skeletal base.
Any idea ?
Edit: I realized I didn’t try the thumbnail map. However, trying it didn’t work either. I’m sure the system works and I’m doing something wrong I just thought it might help myself and somebody else that might run into the same issues while waiting for the merge tutorial