They’re all so cute! I like the third best because it’s family snuggle time, so the focus seems more on family bond than on each member’s focus decorating different parts of the tree or snowman. Even tho they’re looking at the book you’ve got the little one snuggling up to dad and one very in sync focus on the book page. Also like this one because it seems more candid, looking through the fort door into their space.
I agree more Christmas focus for the fort tho, liked the suggestion on red and green lights, cookies/milk, maybe a Christmas pattern somewhere, matching pjs or Santa hats, maybe just think about how you dec your own place and put something personal to your family like an heirloom ornament or something recognizable to family and friends who visit your home.