MSOCS,
Perhaps I can help here (perhaps not....)
The F-35B is certainly designed as a 'strike' aircraft - but it's a 'strike fighter', and is certainly capable of carrying out AD (or CDA?) if called upon. With 20 aircraft embarked, they certainly could do both at the same time, if required. By the way, I'm calling on experience of much smaller ships with much smaller decks and smaller complements of aircraft. However, I do recognise that whatever 'maritime aviation' ends up looking like on QEC, it won't be anything like it was before.
The central issue here appears to me to be who exactly will decide what the aircraft do when they are embarked. How would the JFACC/ATO construct work with a QEC carrier in a fleet that may be required to change its location, speed or course as local circumstances require? Who would make the call to send every aircraft on board on a strike mission and leave nothing on board for DCA? Would a DCA tasking require aircraft constantly in the air, or on some form of 'alert'? How many aircraft would an 'alert' DCA task require? Just how would a QEC carrier generate a strike package? How big would that strike package be? What would be the expected launch and recovery rates? How long would a QEC be required to maintain these rates?
Now, I don't know the answers to these questions. Nor should I. I'd hazard a guess that there are all sorts of planning assumptions going around to scope them out. All I know is the war you end up fighting is almost never the one you expected to fight. Planning assumptions never survive the first few months of any war. Air operations are no exception.
So, I sincerely hope that whoever eventually runs the 'air' show off the QECs, they have the following tools in their kitbag:
Aircraft and aircrew able to carry out as wide a range of tasks as possible
Command and control arrangements that can recognise and react to rapidly changing circumstances without referral back to a 'central' command.
A concept of air operations that exploits the ability of the carrier to manoeuvre, as well as sustaining high tempo air operations.
Best regards as ever to all those rebuilding UK fixed wing naval aviation...
Engines