Does it include a compartment for sleeping bag?
It does not have a dedicated compartment for a sleeping bag but you could fit a warm season bag in the main compartment. But you would not be left with much space for other items. There are two loops on the outside on the bottom of the bag where you could attach a sleeping bag though.
Is it good enough to carry lots of books, a laptop, a water bottle, and a lunch box around? I need one for school and may carry it all day around the campus. I'd like a light backpack that can hold heavy stuff.
In my opinion the Solaris 40 is really good for the task. I've used mine for some time now, and it is really comfortable, even with a heavy load.