Hi everyone, I am designing my first rack, and I'd love a little advice/critique on how to complete it. I have some experience with analog synthesis on vintage normal and semi-modular synths, as well as some VCV experimentation in the process of designing this thing.

Purpose: a "general" rig, educational modular journey launch pad, intended primarily to:
A) Teach a potentially completely unexperienced but genuinely interested person or few (one at a time) the basics and potential of modular synthesis as a flexible musical and joy tool.
D) Have all the tools to give them an early-intermediate mastery of substractive synthesis.
S) Be a fairly flexible, intuitive and user-friendly enough jam/toy box for them to eventually confidently fiddle and experiment with. Doesn't have to do anything specific particularly well, for example it does not need to be able to do an EDM set or proper polyphony on its own.
R) Have enough tools to, as an endgame, give them enough knowledge to confidently reseach and understand more complex modular/synth stuff on their own so they can sod off.

Problem: I already have some stuff that I got locally that fit the bill to me, and I am not 100% confident in my plans for the last 58hp. I would appreciate some sage input on that one. Things I definitely want there:
A) Mod sources aplenty, Envelopes and LFOs (with sines!). Flexible in/out sync/trigger capabilities are very desired.
D) Multi effects. Tap tempo and ext clock sync are very desired.
S) A basic quantizer maybe?
R) Whatever most basic utilities it will need most considering what I already have, and whatever possible existing imbalance needs fixing. This is where I'm at a nearly complete loss.

Things to keep in mind:
A) I do have a non synth-specific, but a fitting and decent external ecosystem: 2-ch scope/amp/EQ/speakers/mixer/phones/ADC/DAC/DAW/PC/DI/splitters/patchbay/effects. I have the case (TipTop Mantis), so the size is a given. I have the tools and skills to solder through-the-hole DIY components or reconnect a wired switch, but not the more intricate stuff.
D) I prefer modules that lean towards obvious controls with intuitively visually indentifiable control positions. Menu-heavy modules with arcane control schemes and unobvious function seem to somewhat go against the educational (zero to early intermediate) purpose, even if more powerful.
S) I am on a budget, and I am buying used, in the EU. If the module is not realistically obtainable this way, it might be a hard sell. If the module is around or over 100 EUR and only "does one thing for one channel", it also might be a hard sell. It is not proper, but it is the reality of my situation at this time. The plan is to eventually phase out the less pleasant low-end stuff in the upcoming years, but right now it's either something like this or an AE modular.
R) The only intended external controller so far is a Keystep 37.

Please ignore the relative module locations, I will deal with that once I know all the modules.

Here's what I already physically have, I'm not above swapping out one or two modules:
ModularGrid Rack

Here's my amateur take on how to complete it:
ModularGrid Rack

Thank you so much for taking the time to suffer through this, please share any suggestions/critique, it will be most welcome. If there's some potentially useful info I failed to give, let me know. Cheers!