You can't have weapons on the map, but you can have ordnance drops.
On to the map: I don't/didn't particularly enjoy Fat Kid, because the game just isn't enjoyable for the infected, or flood in this case. However, if anyone can make these "classics" enjoyable, I will solute them. My only advice for taking up this role, is to perhaps add a new mechanic, an original idea, and use it to give "Fat Kid" a unique edge.
Judging by the images, may I suggest adding slightly more cover in the open areas- for the flood? I found that in the original, the spaces were too open, and players would continuously blast the Fat Kid back, until some mindless player decided to take a risk and get too close. Also, there appears to be too many turrets; the normal infected may not stand a chance against them. I suggest playtesting this map multiple times, changing things, fixing bugs, etc. Just to achieve the best gameplay possible.
I wish you best of luck on improving this... thing.