[Rollo]

The space monster planets cannot be found with sensors. Well, at least they shouldn't. Are you certain that you uncloaked one, Taz? I'll have to look at that again. Maybe I made a typo somewhere with the Monster Sector Cloak. But you can also 'cheat' by turning planet names ON. The planet names will be floating in seemingly empty space.
You can destroy them by blowing up their sun. Find their home system with help of the borders screen or the 'planet name crutch'.
No, they won't surrender.
Like Phoenix said, you have to do some editing to use them in the normal game. And also have to create new .emps for the other races.

Rollo