There should be only 1 date-time picker control and two radio buttons (1-Weekend , 2- Holidays ).
Condition 1- on selecting Weekend radio it disable weekdays in that same Date Picker.
Condition 2- On selecting Holidays radio ,it enable only all those days which are present in a SharePoint custom list named as Holidays, having column HoldiayDate(Date & Time type).
By Default Weekend radio will be active.
Shiv Sharma