Historically, and likely, the end of February 2020 is correct, though the program consolidation puts a "probably" into it.
How are you going to earn 75 night credits in 31 days? Is there a Marriott equivalent to SPG Pro/Event Planner program that earns personal elite night credit?
Only nights personally stayed and individually billed at participating Marriott brand or Ritz-Carlton hotels are credited toward Elite Membership achievement and renewal.