Wow, you are right. Fanime does not have cosplay chess. It seems odd that an anime convention as large as Fanime does not host this event.
I have never actually participated in cosplay chess except as a spectator. Nonetheless, I have seen it run many times at other conventions. Running cosplay chess takes a fair amount of planning. At other conventions where it is held, cosplay chess is a very popular event; it can attract crowds almost as large as the Masquerade or Black and White Ball. What space could you use to hold this event? In the Tom McEnery Convention Center, Ballroom A is probably the smallest room that can accommodate the chessboard and the audience. Unfortunately, Fanime uses it for their theaters. Meeting Room J can just barely accommodate the board and pieces but certainly far fewer audience members than would want to see this event. Exhibit Hall 1 would be adequate but it is used for Artist Alley. It sounds like you may have to consider an off site facility, perhaps the Civic Auditorium.
Once you get the space, what are you going to use for a board? Using tape to make the board is a cheap solution but tape leaves a sticky residue when removed. For this reason, the owners of the facility may not let you use tape. Also, if the squares are not of contrasting colors then the chess pieces tend to become confused as to where they are suppose move and stand. This will happen many times because pieces leave the board every time a battle takes place. Sakura-con uses specially colored mats that help cushion falls. However, this is an asset that they purchased and they must store it, lug it back and forth and assemble it every year. They are also subject to wear so at Sakura-con, chess pieces are specifically forbidden to wear shoes. How big should the squares be? Three-feet across may seem adequate but in the early part of the game, the crowding of the pieces could make it difficult for the audience to recognize costumes except those that stand on the near edge of the board.
What kind of game or games do you want to run? From what I have seen there are three types of cosplay chess games: scripted, unscripted and adult. In a scripted game, the moves and who kills whom are already predetermined. For chess pieces, this could be helpful because they can rehearse their moves ahead of time. The scripted game is not as fun as the unscripted; its predictability can make it feel like professional wrestling. However, it is probably the best choice to start if you have many people who have never played cosplay chess. The unscripted game gains its charm from its spontaneity. In the unscripted game, the kings or off board chess masters determine the moves. This gives many cosplayers a chance to break the fourth wall and comment about the game while hamming up their characters. The adult game is basically an unscripted game where raunchy jokes and coarse language are allowed to become part of the humor.
For participants, cosplay chess requires more than just the three hours to play the game. Other conventions typically require an additional one hour meeting on the morning before the game. Attendance is mandatory and any piece absent is cut from the roster. The primary reason is to review safety rules. You may want somebody from the Dojo to assist or give a few pointers on how not to get hurt. This is also a chance for all characters to meet each other and become familiar with each others’ tactics. Not everybody is going to know the offensive and defensive techniques of every character and this would be a good time to create a death scene that they can sell to the audience. Cloud Strife would probably make straightforward attacks with his big sword. Ash Ketchum would probably say, “Pikachu, I choose you.” Then an off board Pikachu would rush in and electrocute his opponent. Yuki Nagato would probably make her opponent disappear by saying something like, “Initiate file erase protocol 95110.” Hard Gay could make his opponents flee in terror simply by inviting them to wrestle.
How many participants do you need? Due to inevitable no-shows, you are going to need lots of pieces. Extra pieces are needed to replace those who cannot participate. They can also serve as off board summoned monsters, as in the previous Pikachu example. You will probably need several ninja. They will help pieces by telling them where to go and stand. This is necessary because many pieces may not be familiar with the rules of chess or may simply forget what in square they stood. Ninja can also help carry microphones if you have them and help with seating and controlling the audience.
Which characters do you pick? Well, it is not easy being a piece. At some conventions you have to audition to become a piece. In this part of the process, you can check to make sure the costume is appropriate and sturdy and that the props, even if peace bonded, do not pose a threat to the safety of others during the mock battles. Generally, people with skit acting experience (as in the Masquerade) are favored. If you are looking to create a theme, you can favor one costume over another. If you have enough characters, some themes could include good versus evil, anime versus video games, males versus females and retro versus contemporary.
These are my thoughts about starting cosplay chess. I wish you the best in this endeavor.