Claw-
For sinking stations just....
1. Begin Special Build Mode
2. Build your stations
3. Execute sink scenery
4. End Special Build Mode.
When it sinks other sutff as well, that's an error type thing. I have realized that I don't think it works on stuff like tower rides because when you right click to add the stations, the build more tower pieces construction box opens as well. So it sinks everything.
That's why I'm thinking the coaster's gotta be a complete circuit/nonhacked to sink stations. Just a guess, though.. i'm not experienced with this one.
Fool-
End Special Build Mode restores clearnaces
Vampire Freak-
No.
Everything else has been answered, I think.