Jambo Paul!
You are in the home stretch now. Your Walt Disney World Resort vacation will be here before you know it!
In my experience,
Online Check-In is a huge time saver. There will be a designated (and often shorter) Online Check-In line at the Front Desk and because you select your preferences in advance of your arrival, you will just need to confirm your information with a Cast Member.
I don't think you should have any issues with your reservation time at
Boma - Flavors of Africa with a 6pm arrival time, especially if your room is located in Jambo House where the restaurant is located. If you plan to stay in a Studio or Villa at
Disney's Animal Kingdom Villas - Kidani Village, you may need to allow a bit more time to make the walk from one building to the other.
It sounds like your vacation will get off to a delicious start, Paul. Make sure to save room for a Zebra Dome, one of my favorite desserts at Disney's Animal Kingdom Lodge!
Happy Planning,
Andrea U.