I think I just learned this the hard way but it appears that the various "Kadet" parts on the CZ webstore like recoil/firing pin springs, spring guide, and possibly front sights do not fit the new Shadow 2 Kadet kits. I probably should have thought about it since the Shadow 2 Kadet kit is very new and looks like a different design than the older style.
The recoil, firing pin, and recoil guide rod that showed up today are all way too small than what is in my Shadow 2 Kadet
I didn't order one but it also looks like the front sight is very different. In that the Shadow 2 Kadet has a short front sight "post" with the mounting screw in front of the post screwing down into the slide, where the other "kadet" front sights I see appear to be pinned from underneath through the slide.
It wasn't much for the parts so I'm not too worried about that, but I put out an email to CZ just to verify and see if I can order the same parts for the Shadow 2 kits, a search on "Kadet" on the CZ webstore only reveals the parts I ordered.