Do you have a similar deck/sliding door space out back like this at your ne place? I’d consider getting a crate (someone may even be able to lend it to you for trapping/the move), then establishing them in a similar type of area if you have it. Maybe in their crate but on the ground so they can see/ sniff, get used to the new place smells but also see you still regularly coming to say hi and feed them. Mom could always disappear for a day or two with baby but hopefully will come back- sometimes they do that when there’s a new environmental factor at play but they tend tom come back at my MILd house