How are you planning on sending note information to this rig? I see no form of note sequencer or MIDI in.
The Maths can be used as a modulation source. But I don't think it's a substitute for a true LFO or CV generator.
The Intellijel Quad VCA will do for now as a mixer. But I would suggest a dedicated mixer to free up the VCAs to do their intended jobs.
As Garfield pointed out, if you're using Intellijel 1U modules, you'll need an Intellijel case with a 1U row. Note... only Intellijel compatible 1U modules will fit in it. You can't use the Pulp Logic style "tiles" in it.
I would not buy this set-up. You won't get anywhere useful with it. You need a greater understanding of modular, especially utilities and sequencing hardware. I always suggest VCV Rack (it's free) and is a great learning tool for that reason. If you can make patches that you like in VCV Rack, then you probably have enough understanding of Eurorack to put together your first real-world case.