I'm not an expert in license conversion but I'm pretty sure that you have to take all the 14 exams for the EASA license. That requires a lot of studies.
I think they have no N registered airplane so you need an European license. Looks like they found a way to let you fly their planes for a maximum of two years on an FAA license until you have to convert it to an EASA one.
So my guess is if you want to keep the job longer than two years you have to study hard.