I've been working on a Wonky 9-patch I've been detailing in the Fabric Moratorium thread. Sorry, there is no pattern or book I've been following just my thoughts and photos in progress but I think it would work well for your Granddaughter. It's a donation project and I always saw it going to an 8-14 year old girl.
For your project I'd keep the center of each 9-patch the floral print and then randomize the colors around it. I'd also use more consistent pieces, say 3.5" strips for each of the rows.
It's been fast and fun for me. Here's a link to the thread should take you to page 44 (I hope!):
2019 Fabric Moratorium
I have a lot of thoughts about how I started the project before that (starts post 989) but that shows my pre-trimmed blocks and there is a summary shortly after that of what I've done/found out so far.
I'm putting the rows together today, here's a shot of the close-to-finished top. Warning! I still say this is "too loud to sleep under".
Edit: Although it looks wild, until the blocks were trimmed they were all straight cuts and straight seams. It's been very fast and easy and I've had no problems putting together the skewed bias edges together.