Regarding your first question. Yes, it is very straight forward to assing a “Yes” to a Data Element as you can see here.
The example program rule (sorry for the rules not making really sense as I am reusing another program):
Program Rules Variables:
Expression:
Program Rules:
Please note that when using Program Rules and assigning a value to Data Element this becomes greyed out so it cannot be changed (unless the Program Rule expression becames False).