I would contact the GM directly if the stay is important.
Once you hit the 100 nights, it took 5-10 days before I had my ambassador assigned.
The 100 night celebration is up to descretion of the hotel, but I got nothing the past 2 years.
Ambassadors have no power for clearing SNA's, fully automated process.
Last weekend I had a birthday weekend for my fiancee and my ambassador asked all the information regarding her favorite drink/snack so the hotel could arrange something. The hotel only gave a card and some berries, and nothing what I communicated to my ambassador. I was expecting a bit more from a Luxury Collection based on the Ambassador's input and importance of the stay. I realized again that if you want something, pay for it. Same applies for suites.