Hi,
First of all, let me tell you that I've only been using modular hardware for 3 months, and I've started with a tight budget, so I've looked a lot at the price-performance ratio.
Quantizing
You could take a look at the Instruo Harmonaig https://www.modulargrid.net/e/instruo-harmonaig
It is a bit more expensive than the intellijel scales and bigger, but they have a lot more functions, for example chord progressions.
I've only used the virtual version in VCV rack, and it's amazing and very powerful.
Mixing
I always recommend the same, I have it and I am very happy.
https://www.modulargrid.net/e/tesseract-modular-tex-mix-master-section
https://www.modulargrid.net/e/tesseract-modular-tex-mix-4-mono-channels
There are 4 mono channels with CV, send and return, mutes and pan. They are also chainable, so you can grow using the same output. 4 channels plus master are 18HP, but the ergonomics are quite good, at least for me. The price-quality ratio is great.
There is also the Befaco option https://www.modulargrid.net/e/befaco-hexmix but it is much more expensive and bigger, 6 channels 28 HP.
FX
I would stick with the Pico DSP, it is very versatile, takes up little space and you can always even use the granular algorithm, or the exclusive reverb or delay for some percussion.
A good option to consider is also https://www.modulargrid.net/e/erica-synths-black-hole-dsp.
What I do miss in your case is an MI rings or clone
Best regards,
I would stick with the Pico DSP, it is very versatile, takes up little space and you can always even use the granular algorithm, or the exclusive reverb or delay for some percussion.
A good option to consider is also https://www.modulargrid.net/e/erica-synths-black-hole-dsp.