We full time. We only have one 8yr old son, but 3 kids shouldn't be an issue. The loft has ample space.
Couple things we did. Bought a second ottoman at Target ($59.00). That gave us two storage ottomans.
The ottoman that came with it fits under the desk in the bunk room even with the slide in. And can slide out and be used as a place to sit at the desk.
Closet is a bit tricky. I'm working on the divider to make the closet a very narrow 5.5inch coat closet on the outside by the door and a regular non pass through closet for the bunk room.
For now we use some black storage drawers and basket to help organize it.
Here is some pictures of his room. You can store a fair amount of stuff under the couch in the bunk room as well. The table and legs fit on one side of the couch by the wall. We also have a nice storage tote in there to store his dogs stuff and some other things. The couch still folds out with the ottoman and the storage tote in there.
IKEA hooks. They fold up when not in use. Great for electronic items.