Picade is our registered trademark so technically you can only build a “Picade” by buying parts from us :D see https://shop.pimoroni.com/collections/picade-and-arcade
I guess I should take it as a compliment that we’ve become synonymous with Pi-based arcade cabinet builds, though.
I can totally appreciate why you might go for cheaper/different stuff elsewhere, but I’ve snipped out the Amazon link so we’re not directly promoting the competition.
Now, onto being helpful instead of a pedant :D
From your build list it looks like you’re pretty much set. I’d probably pick up a case for the Pi to protect it from any metal components left lying around during the build. The last thing you want is a fried Pi when you fire it up for testing.
The other thing you may want is some sort of audio output. You can use some basic PC speakers, or a USB speaker perhaps.
You could forego the expense of a Flat Pack kit and get some old cardboard to upcycle into a cabinet. It’s been done on this forum before and truly embraces the spirit of a hacked-together project albeit it might be a little involved depending on how much time you’ve got- see Cardboy Arcade - Upcycled Raspberry Pi Arcade machine build log