If anything, Hasbro will show some clips from the movie to press and owners of the main TF fansites like Seibertron.com and TFW2005. That's what they did in 2007 with the first movie.
To answer the other question about admission. There is general admission on Saturday and Sunday every year. It costs $25 and that allows you into the dealer room after a set time in the day as well as admission to the panels.
However there are also preorder admissions. Normally 2 or 3 different versions. These are expensive $200+. But they net you the con exclusive figures for the year, give you early access to both the dealer room and the panels as well as letting you go on tours of local museums and such. This also gives you special rights as a paid convention goer like not having to stand in line to enter the dealer room. Last year (and it varies slightly each year) you also received the Botcon Transformers comic drawn and written using the convention figures, a pin, neck lanyard with pass and access to the Awards Dinner.
I'm the head moderator on Seibertron.com, the leading Transformers fan community, so if you guys have any other questions or whatever, feel free to ask. Sadly I won't be attending this year. Just too far for me. And planes freak me out.