Further to what Fulminn said, those opportunities arose over a 7 month period. How do I know? Because I am in the pool at OAA. Wizzair required well over 250 flying hours, Volotea was flying the B717 and you had to pay €27,000 for TR for it.
Air Atlanta Icelandic's Cruise Relief FOs are not flying at the moment, and as you say Jet2, one must work in Ops for 18 months before being placed on a 734 TR course.
The problem with OAA now is that, since it was taken over by CAE, CAE have decided to add their schools into the mix. This means that job announcements don't go to the 75 cadets in the OAA pool, but to the 400 overall pilots trained at an integrated course at CAE. In essence, they have destroyed what OAA was all about unfortunately.
Prior to this, OAA was great. As is CTC. In fact, I'd go for CTC.