1: no such thing as too much/too big an outworld. The nest can be too big, and that can lead to bad situaitons, but the outworld can't get too big for them.
If the nest space is too big, they don't like it, they want a cozy tighter space, so if we put them in too big a nest, they might start using their trash to fill up the empty space they don't like. And keeping their refuse to rot where they sleep and raise the babies is unhealthy. While the "outworld" is just open space, so they will ignore/retreat from it back into the nest, if they do not like it. You can hook up all the outworld you can provide space for. Just don't hook up too much new nest until they are filling up the current nest space well.
2: Just keep an eye on their food supply. Don't assume to put more food in on a schedual, but look to see how much they still have first. If we give them too much insect too fast, some of it could start to go to rot in their nest, again that is unhealthy for them to live with such refuse where they eat and sleep. Seeds can store a long time, it's ok if they keep a pile of those around, but bug parts and other such things start to rot fairly quickly. So best to keep watch and not give them too much too fast.
3: generally speaking from my own ants, workers move the larvae around regularly. With the main brood pile being moved back and forth between the hottest and most humid parts of the nest a few times over 24 hours. With there being two main brood piles for my ants(pogonomyrmex occidentalis). One pile is the feeding larvae, the other is late stage larvae done feeding and pupae. It's the late stage/pupae pile they tend to move around the most.