I'm sure it's possible. People have managed to cram two floppy drives and a hard drive into those cases (with a custom mounting bracket, of coarse). It all depends on the size of t…
Nah, the caps are on the top, like the small "can" like thingies you see on the motherboard.
I believe every Mac has caps, but the SE/30/Classic II/Classic/SE/IIci/II/IIx/IIfx/LC …