When can I proceed inbound in a hold in lieu of a procedure turn when cleared for the approach?
You don't need to do a full turn around the holding pattern, you can just cross the IAF and proceed inbound. This is from the AIM 5-4-9(a)(5):

The holding pattern maneuver is completed when the aircraft is
established on the inbound course after executing the appropriate
entry. If cleared for the approach prior to returning to the holding
fix, and the aircraft is at the prescribed altitude, additional
circuits of the holding pattern are not necessary nor expected by ATC.