Update: the Embarc resorts now list the room types and no longer indicate you need to call to book. Booking window is 7 to 186 days, which lines up better with Max booking window. I scrolled through the dates for Zihuatanejo as I had been looking at Mexico and saw no availability yet for that one. No availability showing for the first couple of months in Sandestin or Canadian ones either, but I didn't check all dates/room types.
On the annoying side, they put HGVC Zihuatanejo above La Pacifica on the list, meaning HGV Max owners have to scroll down past an Embarc resort with little to no availability to see the first legacy HGVC resort. It's not a choice driven by making it alphabetical as Cabo Azul (also a Max resort) follows La Pacifica. Same thing holds true in the Florida Gulf destination though I'm not sure it matters there as much given the availability of those resorts, although they do have the longer Club booking window. If I were designing or approving the interface, I'd put the native resorts with the longer booking windows and greater availability first.