daninr8 Loc: Western Slope of Colorado

This photo got published for the Thanksgiving party, and I'm expected to take the Christmas party photo too. I need to know how I can improve upon this, so I can do a better picture for the Christmas party. Please realize that this photo is going to be taken in the middle of the party, in order to catch all of the party volunteers. I have one chance to get this photo, and one chance only.
C&C on picture greatly needed.
I have the Canon T3i, with the following lenses, 18-55mm, 55-250mm, and Sigma 18-250mm. The lighting is fluorescent with skylights mixed in, so am unsure how the lighting is going to be. I have no extra gear to adjust the lighting (reflectors, diffusers, etc.), so please keep what I have in mind when you think how you would do the photo.
I do have an Amaran Halo LED ring light, that I can attach to the camera.
So with the knowledge above, what would you do? Don't be afraid to ask questions either. Thanks for all the comments and suggestions in advance.

Thanksgiving Party Volunteers

gwdupree

A) Pose your subjects BEHIND the table.
B) Have subjects wearing any other color than white stand in front of the white aprons. (white aprons blend with the white wall). Not directly in front, but shorter people covering some or most of the aprons. Get several shots and NOT the person's head in the foreground
C) Try to keep the wire with the thing on it out of the shot.
Handsome bunch of people !

Bob1190 Loc: Hatboro, PA

Taller people in back, shorter people in front (sitting, if possible)
Get closer
Use tripod
Have fun

jerryc41 Loc: Catskill Mts of NY

And crop away all that dead space overhead.

Jaime Loc: Los Angeles

Good tips. Shoot raw so you can balance the color temp in post or kill the fluorescent and use just daylight and the LED. Shoot smaller aperture (f11-f22) so all are in focus. You may have to slow the shutter down because I don't think the LED will throw enough light for a group, so ask all to hold still. Watch the headroom. Stack the folks instead of putting them in a single row. Faces. Chest and up. Forget the head to toe stuff. Chest and up. Faces are all important. Look how tiny the faces are in the photo above. Good luck, post the results!!

daninr8 Loc: Western Slope of Colorado

What lens would you use, out of the three I mentioned above?

Jaime Loc: Los Angeles

If they are in a single line, you'll need to go 18-55, but if you stack your subjects the 55-250 or the 18-250. My concern with the 18-250'is distortion. Really, any of them will do. When I photograph groups I use a 24-70. Just be careful of DOF and facial distortion. You'll do fine.