Awesome, will work on a flyer tonight. What rules are you doing? Are all gametypes and maps a go? (Flag, Bomb, Territories, Slayer) MLG is currently under v3 settings which include some community made maps such as Element and Nexus. Also all gametypes and maps can be found here.
As far as headsets go, at most MLG events they are encouraged due to the amount of noise at events. MLG does not provide headsets for its players but does provide a Astro Mixamp for its players with headsets to utilize. I know headsets have been a hard thing to get a consensus on but I know if MLG kids do come they are going to want to use their headsets.
If you need anymore help with any MLG related item just PM me 
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Also is the date set for April 23/24th because that is Easter Break and I don’t think a lot of people will be here during that time.