Sorry for the late response, but:
1.) Can't know for sure, but the signed/numbered book bundle (with swag related to the book) will probably be $80ish, if I remember correctly from Wind and Truth. But you'll also be able to purchase just the book by itself (though likely not signed/numbered) at the con. (For the normal price) But how much you spend on merch otherwise is up to you. Personally I ended up wanting to spend a lot, just because there were a ton of exhibitors who had stuff I found cool (especially artwork), but that varies person to person.
2) Yep it's chaotic, but you should be able to see the things you want to see, as long as there's not scheduling conflicts. It's crowded, but not so much you can't get around
3) Pretty much everything is free, I didn't pay for anything other than my badge/swag, and I did everything I wanted and had a great time. The only big thing that I can think of that costs extra money is the Worldhopper Ball (which I didn't attend, but which I heard was awesome), but that's fully optional.
4) You may have seen Brandon's weekly updates recently, but there won't be VIP tickets this year, just general admission
5) I'd say so - I've brought my roomate one year and my brother another year - neither were super crazy into the books like me, but both had a good time. There's several panels, activities, and things to buy that aren't even specific to Brandon's books. And for me at least, the most fun part of the con is just hanging out with other nerds