First, you were never on the seniority list. Second, union representation is for those on that list. The person you talked to was a union liason, not an official union rep.
As far as I remember, those with offers of class dates were re-interviewed (nothing more than a formality) and given class dates again when the hiring restarted earlier this year. Did you not take them up on that offer? Yes, it would suck to "re-interview" but worse things have happened and you would still have a job.
If a strike were to happen the same could occur again. Those on the seniority list will be protected and those that aren't will be taken care of secondarily. I don't think this is the fault of the union. How would you expect it to be handled?