Hello Tara! Welcome to the Disney Parks Moms Panel.
While it has been a long time since I could refer to any of my "Adults Only" Walt Disney World Resort vacations as traveling with my "crew" and pull it off, I am well seasoned to getting on must-do attractions during peak times.
You are correct that for Guests staying off-property and unable to obtain a
FastPass+ selection for
Avatar - Flight of Passage, rope drop is one of the best times to queue in terms of standby.
The other time I would recommend if your "crew" is staying until Disney's Animal Kingdom Theme Park is set to close is to get into the queue just before the Theme Park is
scheduled to officially close. As long as your group is in the queue before the Cast Member closes it for any additional Guests, you will be able to experience the attraction regardless of how much later than the official closing time you have to wait. Oftentimes, this means lighter wait times as Guests have already vacated the Theme Park and it doesn't cut into your regular Theme Park time.
If you are staying at a Walt Disney World Resort Hotel, be sure to utilize
Extra Magic Hours offered at Disney's Animal Kingdom Theme Park on select mornings but be sure to arrive as early into Extra Magic Hours as possible. If you are staying off-property, I recommend avoiding queuing for rope drop as the influx of Resort Hotel Guests will have already filled the queue for Avatar - Flight of Passage.
Have a Magical Flight!
~Todd