Switching cat litter

I'm looking for suggestions on changing cat litter. The cat who I've had for a year is using Fresh Step Crystals. She likes them just fine. My new cat didn't seem to like them much so I bought Yesterday's News a couple days ago for 1 of our 3 boxes because I was going to have him declawed and I couldn't use clay right after. He's been doing fine with Yesterday's News. So I have 2 boxes with crystals and 1 with YN.

I've decided not to get him declawed and would like to get both cats using clay litter. But here are my questions...

Do you think this is too much change for them right now, especially the new cat?

Is it a bad idea to change from the crystals to clay for my old cat since she just got a new "brother" whom she hasn't totally gotten used to?

I am moving to a new house in 10 days. Should I not make any changes until they are both settled in the new house?

Thank you in advance for your help.

I have found that no matter how old the cats are, you can always change the litter! I've always just made sure that I gently rub their paws in the new litter and I keep the box in the same location so that they know what it is for. You can also add a small piece of their poo to the new litter because they are all about sense of smell...that really worked for litter training the kittens. And just a note, I have also found that when you blend two different kinds of litter, say crystal and clay, that neither does what it is supposed to and you end up with a big smelly mess so it is just better to go cold turkey! :D

Do you think I should wait until they get acclimated to my new house when I move in 10 days or should I do it now and give them 10 days in this house to get used to it? I'm thinking that if we do have any "out of box" episodes, I'd rather have it happen in this house.

Well that is up to you I guess, if you want to wait until the new house, it shouldn't be a problem...and as for the "out of box' experiences (sound sci-fi huh? LOL) there is a spray called Folex that will get ANYTHING out of carpet and it is so easy to use (trust me I am one of those lazy cleaners!).
Cats are surprisingly adaptable creatures... so chances are they could handle the move and new litter all at the same time, plus you'll prob have a new litter location for them to get used to at the new house anyhow right? So you'd have to do the paw-rubbing thing anyhow! :D

Oh and congrats on the new house!