I believe the intent was that any contract F/O's employed - for either B737 or A320 - would not be permanent, all contract with no seniority dates applicable.
When the contracts were completed THEN the numbers would be crunched and offers might be made for permanent employment with seniority starting from the END of the contract.
At the same time they would still be recruiting "intake" F/O's as permanent during the rollover who would have a seniority number from the day they joined.
Regards contract Captains in the early days "expectation" was at the end of contract positions as F/O's would probably be expected and IF the stars lined up and there'd been a mass exodus of Captains AND there were no upgradable F/O's then MAYBE there'd be Captain slots to be filled.
Set your own odds of THAT all coming together!
Then the pilot deal was made with the V group.
And that, as they say, was that!
Once again only my understanding.
Cheers.