First, management wants to sell this pig and luxuriously line their pockets in the process.
Second, as long as the pilots are working under separate contracts, the company is not really salable.
Third, as even the Ninth Circuit opined, it is unlikely that a contract containing the Nic would be ratified in the near term.
Fourth, the company really does not care what seniority list is used. They do not care to be sued, however, by ignorant forces that do not understand the RLA. Ignorance, though destined for ultimate failure, still takes time and money to fight (see Addington vs. USAPA.)
With all this in mind, the company wants itself declared by a court to be immune from such lawsuit. That taken care of, they will likely resolve the single contract issue fairly soon afterward. (The contract will mysteriously resemble the American Airlines pilot contract in terms of compensatory rates of pay.) Since a non-Nic contract is the only one likely to be ratified in the near term, that is the contract the company will sign.
Of course, ignorance will again prevail with another ludicrous DFR suit against USAPA, but the company would not care at this point. They would have what they want, and they won't really care if a group of pilots wants to sue their union. They (and any successor corporation) would be immune, and the LCC could be marketed.
But they need the cover of immunity from the court before they can get what they really want, i.e. obscenely rich from selling LCC.