The new T&C make it clear that elite benefits are only guaranteed for qualifying rates. Those don't include 3rd party bookings, so you wouldn't be guaranteed elite benefits on any 3rd party bookings.

That being said, some hotels may still honor your elite benefits at their discretion. I'd imagine that would be most true for returning guests who already have a relationship with the hotel or for those with the highest level of elite status. But there are no guarantees.