Congratulations on the new ones! They look absolutely adorable. Sorry to hear that they had a fallout though.
Generally they would get annoyed if you try to add/renove things when they're still inside the cage. It's better if you remove Franc from his cage when you dump in more bedding. You could place him in a playpen until you're done sorting out the cage.
I think it would be best if you could provide him all the substrate needed now, since he's still very new to the new cage. Adding it once he's more used to the cage can cause him stress all over again as he tries to adapt to additional substrate.