FR are sure going to a lot of trouble just to say nah...... let's both bother with all this shinanigans, we' ll fly to SEN with a DUB based aircraft and skim the cream.
However, I wouldn't be surprised if a route or two didn't last and the extra capacity used on the DUB route. But so what?
If Ryanair are as pessimistic as Sharklet_321, I really don't think they'll come.