The 7 x A321’s will be under the Jet2.com AOC which means their are either owned or leased. They will be fully crewed by Jet2 pilots, cabin crew and engineers.
The initial 7 are ex TCX aircraft - the are definitely not the ex monarch cook ones as they are different engines and there is only 4 of them. This would not be economical sense to operate two different engines on 7 aircraft.