If this is one's "only hope" then all hope is indeed lost. Changing unions won't nullify the Nicolau Award nor the need for a joint contract. It's just a knee-jerk and emotional response. The AAA MEC is deceiving its members once again with false-hope and any new union will end up with the same leaders.
Again, don't have a dog in this fight, and sometimes that is what it takes; an 'un-bias' view of the situation.
This would be a question for a skilled lawyer with experience in RLA Law, and not sure if there is any case law on the issue. However, that said, its face, I do believe that leaving (de-certifying) ALPA will 'nullify' the award, as this process was done under 'ALPA merger policy' by agreement by the ALPA MECs and ALPA national. And, if the 'award/list' is not yet put into effect, and the pilots are Nolonger in the ALPA organization; don't think the group would be under any obligation to follow 'alpa merger policy, or any other alpa policy.' If they 'de-certified alpa' prior to having a joint contract and prior to the new list being put into effect; then they would simply set up 'bylaws' in the new union stating that Seniority will be based on LOS (length of service), and negotiate a new contract that would cover 'all' of the pilots of the new union. And, as when You first vote in 'initial representation' whatever the 'status quo' is at the time, must be maintained, meaning all of the current contacts/agreements in place will remain in effect until replaced by a new agreement.
I could be wrong but that is the way that I look at it right now.
And, as a side note, I do hope that they 'de-certify' alpa, to send a message to alpa national, as others are right that alpa national has 'totally failed' in representing its membership. A few examples; age 60, failure to push congress 15-20 yrs ago for 'pension reform' which probably would have saved most pilots' pensions, failure to come up with a comprehensive policy regarding RJs and enforce it, which probably would have kept everything over 50 seats at any alpa carrier, as 'mainline flying,' and finally failure to come up with something more 'specific/detailed' regarding alpa merger policy (as opposed to their one page/vague worded policy) which led to this current issue, and etc. etc. And, well when it comes to alpa's failures, I could go on and on.
ALPA NEEDS TO GO, and I guess this is a start.
Just my $0.02, for what its worth, now feel free to 'rant' away.
DA