Hey , sorry to answer late I just received the notification
I saw this today, (Unreal Engine Inventory Examine Interface - YouTube) I guess it’s what you mean 
In fact, all my meshes are already in arrays of structures, inside my character. A structure for rods, one for reel etc. The studio BP is placed in the level, at -5000 on z and is not destroyed.
In the menu widget, I basically use switchers so when I click on rods I have a list of all possessed rods with a viewport: (don’t look at those poor graphics ! )
The problem I have is in the stucture, or should I say the architecture of the blueprint.
I had something like this :
As you can see there are a lot of components, variables, and I have more studios to put in the blueprint, ( and also I have’nt found the way to use a camera with the scene capture ).
I thought about creating a parent blueprint with child, but it will make a lot of assets in my content browser.
Now I 'm trying something else. I have only one blueprint with public variables used in the construction script (scale of the dome, light intensity…)
Then in another blueprint, I add child actors in the construction script:
By promoting each one I hope I’ll be able to send them message individually via my widget, as it was before but with less objects.
But I still don’t know if it’s the more efficient way. I could also, instead of creating several children in the construction script, create only one studio and set specific parameters when I switch (when I click on rods, the studio changes to match , the dome get bigger, the light changes …). In this case I would use variables to keep track of view settings, and I could also save them aswell as menu status, so when the player reopen his game, the menu is the same than when he quited .
I’m sorry if I’m not clear sometimes but even in my own language I don’t always understand what I say …