Hmmm... Maths is a very flexible module. It really can do a lot (check out Loopop's YouTube videos), and would probably cover many of the functions of the Quadrax and Blinds. I've got both Quadrax and Maths in a larger case and I'm finding new uses all the time. You may find a Maths/Batumi combo valuable in this case instead of Quadrax/Blinds, but everyone works differently. Maths was not immediately intuitive for me, but I'm really appreciating it now.
I question the value of the Data in a small case. It's a lot of hp, but again you know your workflow and needs better than I do. The factory build of Clouds is discontinued and you will probably pay a premium for an original build. You may want to take a look at some of the smaller clones like the Monsoon if you want to save some money and space.
Finally, will you be relying on Marbles for all of your sequencing, or do you have an external sequencer? I would take a look at something like a Varigate 4+ if you want to do some more sequencing in the case. Adding some mults and switches might be something to look into as well.
I'm sure some of the other folks here will have other valuable advice for you. Good luck and have fun!