For your first question, answer is simple. You ve to programatically reset the buttons back to Enabled mode.
For your second question, the user cannot click on a Disabled or Disabled & Grayed out button and initiate a correspomding, unless & until that button is programmed with its Mouse Down/Up event using the Event Structure method of programming.\
See the attached VIs in LV 7.1.
Repost here for more doubts or queries.
See the attached VI for a bit of modification of the booleans being put to Latch mechanical action.
Thisis what Albert Geven had mentioned in his post.
Do you need something similar to this ?