I'm guessing that striking was not an option due to the fact that flexi crew were not employees of easy. However, as NR says, and I'm inclined to think the same way, management will probably offer a less appealing contract to these newcomers when it's time to move to the LHS. I believe this because at day one they have hooked those pilots willing to accept poor terms. They now know the calibre of the new flexi crew (I understand there maybe 10 of the 200 offered a perm position). So of course they will "try their arm" when it comes to promotion, profits are priority (even though they say its safety, hahaha).
So, as these flexi crew will now definitely be permanent employees (having served their 12 months flexi crew probation) ADM and peers will be happy and legal to strike to make sure their new peers are receiving the same pay for the same job. So I guess we'll see strike action at easy in 2-3 years