Absolutely lovely photographs, gorgeous chooks and coop! So generous of you to have shared with us.
Your nest boxes remind me of Hollywood Squares! So cute!
I have Welsummers ( I think one of yours is a Wellie, too, unless I am mistaken) and mine started laying just after 4 months. Once in a while I still find one on the floor of the coop.
For the floor I am using ledger paper from work that comes out the the shredder looking like sand, it is so fine. We use soy ink, so it is safe. I have it down thick (about 4 inches) , and stir it every day. I also pick up a lot of the droppings right under the roost for the compost pile, and we have a fan in the window, so all is very dry. I have a bit of straw in the nest boxes, but the girls are always scraping it out! They only want a bit around the edges.
I think I may just see how it goes through the winter, and compost the whole thing in spring.
I use a nipple waterer in the coop, but they seem not to like that so much, and once I let them out in the yard for the day they prefer to drink from the metal dishes I put out, and refresh with ice cubes a few times a day when it is this hot. They do love cold water!