BaronPraxis,
I'm not sure what you mean about changing objectives. If you want them removed from the objectives screen once they are done, have the objective trigger activate another trigger which has an effect to deactivate the objective trigger. I hope that's not as confusing as it sounds!
For the non-clickable part, have a trigger which loops with a condition object selected and effect change ownership player 1 to player 1. (The trigger can be activated and deactivated when you need it.) I haven't yet played Ulio but I'm guessing that's what was done.