resign seniority
From what I have seen and heard both personally and through other pilots is that EJA will have you sign a seniority resignation letter. This will go to your previous employeer and union.
I believe that you are still required to sign a training contract for two years for the amount of your type rating. (The ultra is $13.5k, and the citiaion X is over $30K) When I interviewed two years ago it was the first think discussed in the interview. I have not heard to what extent EJA will pursue reimbursement for training costs if you break the contract. It is prorated over two years, 100% due if you leave within the first 12 months, 50% due if you leave with in 24 months of hire date. I dont think it matters if you go to sim or indoc first.
EJA wants to hire and train people who are in for the long haul, not just a place to get a pay check while on furlough. Read everything they give you and think about what you are signing. EJA is a great place to work and will only get better you won't be sorry!