Ryanair would never use pre clearance in SNN, believe it costs more than in the US and even more than DUB. There would be little scope for a deal as US staff the facility and not controlled by SNN.
Cheap loco will only work direct, there will probably only be a handful set of seats very cheap but the rest will be the same as current carriers or just a little below them. The taxes alone to the US make such fares never possible. FR will be similar to DY if not slightly higher cost base if crews from EU were used and they would be using older less fuel efficient aircraft.
I notice MOL said he wouldn't go from DUB because EI would dump on him.
Still would be interesting to see how fr would actually do t but I think MOL will of left the company before it happens.