They would have 2 options to add a new option at WL. They could do a new and totally separate (legally) resort with a new RTU expiration and separate inventory. Or they could add a new section and roll it in to the current resort, inventory, etc. For the former it'd be no different than a new resort elsewhere where even the current VWL owners would only have 7 month access and vice versa. For the latter, they'd have to extend the land lease or have the new section be the same RTU expiration of 2042. Any extension would require some sort of interaction with the current owners. They have to do an extension of some sort that would extend the current VWL owners or get them to sign off on a waiver much like they did with OKW.
As for what is likely to happen, it depends on info we don't have such as volume and retail demand of the points at the current price and expiration. I'm not seeing a large volume addition expiring in 2042 but if it's fairly small it might work out. Of course they could get creative with fixed weeks, discounts, other incentives like they did early at SSR.