Hi Terser. Thanks for de-lurking.

Regarding your second question, there are way to prevent rebellions or at least make them less likely. See the links on rebellions in Table of Contents. Also, there might be a such a mod as you ask for, but I can't say for sure. Here's something that might help: No Mass Rebellion.

Hmmm, my search didn't reveal any mods that eliminate rebellions, which doesn't mean there isn't one. I'm some help eh?