Well the people putting this convention together have contacted EVERYONE and I do mean EVERYONE associated with the series. As of today, December 12th, here is what was told to us on the message board for the convention.
Laurence Fishburn said absolutely not.
Lisa Zane would love to attend, but will be out of the country.
Tuesday Knight, Kristin in part 4 doesn't fly or drive, so getting her to Texas becomes darn near impossible.
Patrica Arquette, who played Kristin in part 3 has said she would love to attend, but is waiting to see her filming schedule for the tv show she is on.
Johnny Depp's people said to contact them at the end of the year to see how is schedule looks for next year. As far as Johnny and his feelings for the Elm Street franchise, I will pass along this fun story I once heard.
Depp had his "infamous" cameo in part 6 and when Wes Craven was putting together "New Nightmare" he wanted to bring Johnny back, but he figured since he was just in part 6, he wouldn't want to be part of another one. Turns out after the film was finished Johnny had said that he would have agreed to come back for part 7 since he does enjoy the films.
***I think this post was long enough and I think I answered your questions. lol
Back to Kim though, I was told by someone helping to book guests, that Kim merely heard about this convention and then she actually called to see if she could be a part of it. lol
Just awesome.

What about Johnny Depp? Or is he too good to be involved with the NOES series..

THis is so gonna rock!
Dont forget. PATRICIA ARQUETTE has said that she will attend schedule pending. SO hopefullyMEDIUM isnt filming that weekend!!!