Wendy,
For the Pop Century question, I would ask to get rooms in the following buildings (in this order of preference);
- Building 10
- Building 6
- Building 1
- Building 3
Note that every building has some connected room options. Some pair a standard room with 2 beds with another of the same. Some pair a standard room with two beds with a room that has a single king bed. Some also adjoin handicapped accessible rooms. Make it clear which you prefer.
Also, in the buildings I noted, many rooms are preferred, some are not. So make sure you indicate that as well.
As to whether or not you have to exit the park after breakfast at Tusker House, no you do not. Just make sure that you time finishing your meal to the park opening time as much as possible, and know that they won't let you wander the park until that time occurs!
Have a magical (and delicious) vacation!