That’s fantastic! What a cool thing you got to do with your school. Funnily enough, I have almost the same set of vintage synths: CS-40m, Jupiter-6, Juno-6, and DX7ii (and a few others). If you can find a JX-3P for cheap then that might be a nice addition. It doesn’t sound like either the Juno or Jupiter and has a great sound unto itself.
The good news as far as the ICs go is that most of them are easily replaced. Almost all of the op amps are still available and the 4000-series ICs are easily available. If it comes down to needing a 4000-series IC then I recommend getting an assortment package from Amazon rather than buying them individually.
One thing to know about this era of Yamaha equipment is that they seem to suffer cascading failures. Yours isn’t exhibiting this, but just be aware of it. Something can go wrong and then poof, tons of crap gets fried. I ended up replacing over 200 components in my CS-40m due to this problem and had to swap guts between an FX-3 organ and an FS-500 (same organ, less cool case) due to all the component failures.
OH! One hot tip: Since you’re getting this stuff for your school then I highly recommend you look for cheap or free organs on Facebook. You can find some really good things for the cost of buying your friends some pizza. Look for Yamahas from the 70s through the early 80s and Hammond models M-3, M-100, L-100, E-100, T-500. The Yamahas E70, D85, FS/FX series, and a few others are all just amazing instruments that I know you will love. Can you imagine trying to buy a beat box, string synth, poly synth, analog synth, clonewheel organ, and a performance controller? You get it all with these crazy things and they’re usually free!