I REALLY hope you would not give them YOUR jepp binders.
No, your atp written will not be good at another airline. The only person I know who does not care about the date or continuous employment on the written is John Trask......the man to see if you need to get your atp outside of an airline.
Yes, you will have to go back through 50 training. I was out of the right seat for a few months and had to do it. 1 day of ground, 3 sims....a warm up, an MV and an LOE. I tried to fail the LOE....did not work even though it should have. ( I gave a clear and concise reason to)