I think if it's a new association then it would follow the Riviera path and have the same restrictions and I think it'd be very difficult to avoid confusion between the two. Not that Disney needs to care about resale but resale buyers need to keep on top of which Poly to buy to avoid restrictions would be confusing.
I think Disney wants to be able to sell the bungalows as a feature for a single association. It'd be weird to tell people they need to buy into the *other* Poly if wanting to stay in bungalow, and then tell the person if they do that it's bungalow, studio, or bust. It worked at Poly for a long time because there were no other options, but expanded room types benefits everyone and making people choose "bungalow and studio" between "studio and 1, 2, 3 bedrooms" seems unnecessary when alternative is taking people that they can stay in any of the accommodations on property. People love studios and expansion into the existing association allows plenty of options for Poly 1 owners wanting bigger rooms to book expansion rooms and new owners more access to freed-up Poly 1 studios. Conjecture, but they could go lighter on expansion studios to make more 1, 2, and 3 bedroom rooms. More 1 bedrooms at twice the studio cost works because Disney gets the same points (revenue) per square foot as a studio, where they seem to make a lot of money. If any studios in the expansion and it's the same association I think they'll need to differentiate from Poly 1, perhaps by removing the half bath or otherwise keeping Poly 1 attractive for a different group, similar to some differences between Jambo and Kidani making them attractive for different reasons.
The only real reason to make it a new association is that they did it with Riviera but we've already seen them expand VGF and fold into existing an association so DVD is not beholden to forcing a new association.
A new association would have a 50 year life but folding into existing association it'd expire sooner. Unsure how Disney does its accounting but they'd make the same money either way (insignificant number of folks with balk solely on number of years when Poly is in the 2060s already), but then they could turn around and resell sooner with an earlier expiration date.
I don't see any reason to go against any of that.
On the other hand I think it's more likely that DLH ends up like Riviera. I think there's some sense behind resale restrictions slowing cost growth but even for me that's really going far the other way.