Congratulations chaps.
I applied for this (although unsuccessful) but was told the only exact terms of the MPL were that you would be offered a 3 year deal on flexicrew after completing type rating and line training. You are only "eligible to apply" for a permanent contract at easyJet after 1250 flexicrew hours.
I guess worst case scenario would be completing 3 years on flexicrew and then not getting offered a permanent contract, by which time you would have done 1500 hours anyway so would have an ATPL.