I'm not sure what the rules are for the art show, but I can definitely tell you that entries for our fanfic/ illustrated fic/ novel / novella/ manga & webcomic contests can be made using pencil, pen, ink, Copics, computers, basically anything legible and discernible is good to go
This is true, as well, for entries in our art contests held in our rooms (Directors and Council, 3rd floor of the Hilton), at Creation Station, including our On-Site Mini Manga contest.
Wade, one of our staffers, ran the Art Show last year, so if a week or so goes by and you don't have an official answer (please forgive that I don't know who's running Art Show this year),
PM me and I'll ask Wade for you
Good luck in both the Art Show and the fanfic contest!
Remember that we also have Fanfic Bedtime Stories and Fanfic Theatre; in addition to submitting your fanfic for our contest, you can read it aloud or cosplay it for prizes! (Or you may have someone else read it aloud or cosplay it for you.) Hope to see you there!