Went to Matilda in late April and the guy at merch booth said that there is going to be one but it won't come out for a while. Don't know about Cinderella.
Yeah, I checked the websites, but since sometimes merch is available in the theatre first, just thought I'd ask. If they were available at the theatre, I was going to ask someone I know who is planning on seeing both shows in a couple weeks to pick them up for me (obviously, when I saw the shows in early March, they were not!) :)