Depends on carrier. I don't see how being a cadet or not will factor into it, they are trained and checked at the same standard as any other pilot.
Substantial sim currency would've been established prior to return to line. Training Captains really busy ensuring all crew being stood up are safe to return to line. For the most part domestic crews will get an opportunity to fly at least once within 7/8 months. A good idea to concentrate on things like safe operation, SOPs, keeping the operation as calm and basic as possible, carrying plenty of fuel, not worrying too much about OTP, giving ourselves wide safety margins etc
I've heard airlines are planning on roughly 50% of domestic capacity by Christmas, which should be enough to maintain a good level of currency among all pilots. IMO it'll be pilots flying widebody and long haul operations who get very few sectors to begin with who'll have a much harder time returning to work, especially those who will be off work for a period of years rather than months.