Some thoughts would be:
- You can test the SE/30's logic board by putting it in the SE and flicking the power switch. That would be useful for diagnostics.
The SE's ps is very likely the same as the one in the SE/30, so you probably could swap those.
The superdrive will work in the SE/30.
An SE/30 is worth restoring to stock, working condition. So is an SE, in and of itself.
The Classic II's CRT will, I believe, work in the SE or SE/30, but I gather not without some fiddling and it is not as simple as a straight swap. I think it has to do with the yoke connection or the like, so unless you know what you are doing, you have the potential to bugger up not just one but three machines.