I presume you'd prefer some information rather than inane replies about relationships between RYR and the IAA, etc.
My understanding (I don't claim to be definitive or expert) is that there are 2 issues - 1) the right to live and work in the EU, and 2) your licence.
For 1), you need a working visa. If RYR can show to the Department of Enterprise, Trade, and Employment (
DETE - Employment Permits Section - nothing to do with the IAA) that they have looked for suitably qualified flightcrew within Europe and cannot meet their needs, they can be issued a visa for you. This would only apply to experienced Captains as there's no way you could make a case for F/Os, and you'd have to wonder how much longer they could argue for Captains in the current environment.
For 2), my understanding is that the IAA (
Irish Aviation Authority) will issue a validation on your FAA licence for 12 months, and that it wouldn't be extended longer than that unless you have completed all or part of your JAA exams as agreed with the IAA.
So, you could regularise your licence position with a lot of hard work combined with the hard flying you would do with RYR. In theory, you could also apply for Irish citizenship after working here for 5 years, but in practice it would be very difficult and take considerably longer.
I suspect there's a quite high turnover of the non-JAA / non-right to live and work Captains in RYR as most will do a year and then leave, but I'm sure some of your colleagues have done it already and some Mesaba guys went to Cityjet on the RJs, so you need to poke around and find someone who has done it to give you the complete picture.
Incidentally, since you would theoretically have a work visa and be registered here, I would suspect that you would have to pay full Irish tax but you could then offset it against your US tax, and do not be fobbed off by any "talk to Brookfield" BS from an RYR recruiter.
Overall, it would be a different and potentially attractive option in comparison with where you could end up elsewhere on contract, but you need to be very realistic about who you are dealing with, there will be no union or wriggle room on terms and conditions, and you're going to have to suck up some stuff you won't like including rosters completely unsuitable for commuting or getting home much.
I hope this helps, and your guys find work.