The OP did not mention paying for a type rating. Bond, Well I would take that, pay for an ATP rating, that would need some thought. However the first Multi Crew job is the hardest to get, turn that down for a possible interview in the new year. That is a big gamble.
I know a few lads who started at Atlantic, most who's next move was to DHL, it is a good start to your career.
I seem to recall that Atlantic wanted a 12k bond back in 09 to go left seat on the ATP, I got a better offer 4 weeks before I was due to start.