Again, I've been gone for a while, can someone tell me what this is and what happens/where minions go if you choose to add them?

It's a new thing they're slowly putting together where you can store and kind of battle with your minions. If you have a GA, you can read the original testing thread in the GA testing forum:

Thread Explaining The Minion Zoo

The link to the Minion Zoo itself is here:

">Minion Zoo

thank you!