Newbie project help: MIDI foot controller


Hi, complete newbie here. I'm planning on building a (quite ambitious) MIDI foot controller with the 320x240 ILI9341 touchscreen. I have a few questions, and would really appreciate some help from experienced builders like yourselves. First, here's a mock-up of what I'm thinking of building, based on the dimensions of this sloped enclosure:


I've been told by friends that this build is actually pretty simple, and the complexity is mostly in the software. I'm a software developer by trade, and while C++ isn't a language I know well I feel confident I'll be able to figure it out. I hope!

Q1) There's not much gap in this design between the screen and button A, of course button A will extend into the interior of the enclosure by at least 12mm. In the pictures for the touchscreen it shows the screen being very close to the left hand side of the Teensy, meaning that button A will be in the way. Does the screen have to go exactly in the position shown in the pictures, or is there a cable so I can position the Teensy somewhere more appropriate away from button A? If there is a cable, where can I order that from?

These red boxes are roughly where the screen and Teensy would be inside the unit if the position of the screen has to be where the pictures show.


Q2) I'm in the UK, does anyone have a supplier they can recommend for all the bits I'll need - breadboard, jumper cables, LEds, footswitches etc? I'd specifically like "soft-touch" footswitches which are quieter than the usual clicky ones I have on my old Line6 gear.

Q3) Given I'm in the UK, is there anything I should know about shipping the Teensy and touchscreen - am I going to get upset by huge international shipping costs?

Q4) 'd like to know whether/how I can store data on the SD card to remember settings, maybe have on-board editing. I've seen a couple of YouTube tutorials but they don't mention the SD card. Can anyone recommend any resources to help me get started using the SD card, or indeed any of this? I believe the breadboard is where I can test all the wiring before drilling any holes or melting any solder.

I've started mocking up the logic in JavaScript to help me decide exactly what I want the controller to do (send individual notes, maybe send chords, send program changes etc). I've also printed on paper a to-scale version of the unit to check my big feet fit! I'm planning as much as I can so I don't waste money and time on a project that isn't going to work. Even so, I really appreciate any help I can get. Thanks.
UK Hobby suppliers for microcontroller stuff include skpang, coolcomponents, pimoroni, probably many more these days. Stuff on eBay is pretty much entirely counterfeit these days alas, and undocumented usually.
Thanks @MarkT. Pimoroni had a lot of the bits I need in stock, so I placed an order for the following (I'm starting from scratch and only have the basics of hand tools, no electrical parts at all):

- Breadboard
- Couple of packs of RGB LEDs
- Large pack of resisters
- Spool of rainbow wire
- Jumper Jerky (pin-pin and socket-socket)
- Pack of headers
- USB host cable

And the Teensy 4.1 development board. Unfortunately they didn't have a Teensy with pins, so my first job will be to solder some headers on so I can plug it into the breadboard. Or is there a better way?

I'm not ordering an enclosure or the any buttons until I've done some experimentation and worked out exactly what I'm going to build. I assume I'll be able to test how switches work by touching two jumpers together, which will allow me to try out my programming.

Thanks for the help, I really appreciate it.