i guess the main reason for this is because i still have questions sorry staff for the the hassle 
and i'm also guessing if we make a more unified board and put questions together it might be easier to answer so feel free to post questions here, for all the other n00bs
Q1 when does ndk close every night or does it?
Q2 if it doesn't close does that mean i could be there all night?
Q3 how hot does it get in the building? (i'm kinda going to be in cosplay so i wanna know if i'll die of a heat stroke XP)
Q4 do preregistered people get any special treatment? (i heard i get my pass quicker in line or something like that)
Q5 will there be any kind of real food sold in the hotel (not pocky and ramune) or do i have to go out to a fast food place?
ummm i think that's it, and thanks in advanced if you can help me
1+2.] It's technically open all night, but unless you're over 18, or are in love with Karaoke, I doubt you will find much (which is good for youngin's, sleep is good.) So I suppose the official time would be after the dance, because that's the biggest thing each night (J-rock on Friday. Rave on Saturday.)
3.] The building has a/c, so unless you have a furry costume, or more than four layers, temperature shouldn't be too much of a problem.
4.]Yes. You get a bag of goodies, you get into the dealer's room 30 minutes before the others, and you get a nifty badge with better artwork than the weekend-of badges (there's probably a few more privileges, which someone will elaborate of.)
5.] Yes, but it is a bit pricey (though not the most expensive food you can buy.) Hamburgers, Hot Dogs, Chicken Nuggets, etc. . . So I wouldn't recommend eating full meals there. But you can buy chips, apples, drinks/water. Which is handy for the convention (try to have a small snack every hour to keep your energy up, and don't skip any meals.)
But for about 1/2 of the price you can hop across the street to Wendy's to get the same stuff. (Except for the fruit.)
Sorry if i missed anything or gave a bad answer