Question 2:
You mean that they can only select one option from 1-3 once, but they can do it whenever? Easy enough ->
Make the trigger "repeatedly".
Inside each of the "menu#.sqs" scripts, put something like this:
0 setRadioMsg "NULL"
Now, the number in front (in the example above '0') corresponds to the radio message number. So Radio Alpha is 0, Radio Bravo is 1 etc. Anyway, what the above command will do is simply make the radio disappear and be unusable.
If you want to use the same channel later, you'll have to play around with conditions and stuff, but for the easy use, the above is how to do it!
Good luck!
Wolfrug out.