I can't remember what your hive set up is, valmom. Do I remember correctly that you have 2 deep hive bodies and 1 honey super for your hive set up? How many frames are filled in the hive body or each hive body?
Bees will store some honey on the brood frames as their pantry and storage for winter. It is possible that your colony is ready for a honey super and if you haven't provided it, they are storing honey in the brood frames.
If you haven't already, I would seriously consider joining your local Beekeepers Association and attending meetings; you will also most likely be able to meet a beek willing to be your mentor. Maybe that beek that held the original classes you attended? If you haven't been watching the hive activity, a local beek would be a good place to ask about the local nectar flow.
If you check the frames for eggs and small larvae as well as capped brood, you can tell the health of the queen and the colony. If it looks like there is a steady coverage of the frame with various stages of brood cell, I would not worry about not seeing the queen. But it is important to check the frames for eggs... I occasionally used a bee brush to remove bees to inspect a frame.
A colony will have about 100 or so drones in the hive during summer, so I would leave the cells alone if you are sure they are drone cells. Of course, if you have an entire frame of drone brood, it could be your queen has been replaced by a laying worker. A worker is a non-fertile bee that can only lay drones.
For ants, you can sprinkle ground cinnamon on top of the inner cover and around the hive. You can also place Queen Anne's Lace flowers on top of the inner cover. Ants don't like either. Both will need reapplied. The honeybees in their housecleaning will remove them. And, of course, ground cinnamon around the hive would need reapplied after heavy dew or any rain.
ime and in reading, mice usually don't head for the hives until the weather gets colder. I would guess the mouse went in for a bit of honey and the bees attacked and killed it. But reinbeau who beeks in MA and ME would have better insight about that in your region. A metal mouse guard entrance cover, which has holes that a honeybee can get through that a mouse cant, if fairly inexpensive insurance for keeping mice out of the hive.