The 55-200 is a 1:4-5.6. (f/4-5.6, not f/1.4-5.6)
He has a couple of typo's in his signature (the 70-300 is also 1:4-5.6).
The only glass CNCO has that is fast enough is the 50 mm f/1.8. It doesn't have the reach, unless he's in one of the very front rows, and really needs to be stopped down to at least f/2.8 for sharp focus and enough depth-of-field (DOF).
The D80's ISO performance is such his usable ISO pretty much ends at ISO 400, but noisy photos are better than blurry photos.
Shooting in low light is one of the toughest situations in photography, and one of the main reasons serious shooters pay several thousand dollars for a camera body that has enough ISO capability so that supplimental lighting isn't needed (D700, $2500). They then spend a couple of thousand more dollars for a lens that is up to the task. (AF-S 70-200 f/2.8G VRII, $2300)
Entry-level consumer camera bodies and kit lenses just do not have the capabilities to shoot quality images in low light without flash, regardless the aperture, shutter speed, and ISO settings.
I would recommend CNCO sell the 18-135, 55-200, and the 70-300. Add to those $$$'s enough additional $$$'s to get a good used AF 80-200 mm f/2.8D. Then sell the D80 to fund acquiring a good used D90.
There is probably not enough time for that strategy to help for the upcoming play and fashion show, but it will get CNCO a lot closer to what he needs for the next one.
I recommend the following mid-level lens lineup for Nikon dSLR cameras having a focus motor in the body:
AF-S 12-24 mm f/4G (this is a DX lens)
AF 24-85 mm f/2.8-4D
AF 80-200 mm f/2.8
If you gotta have 300 mm:
AF-S 300 mm f/4D
Certainly everyone prioritizes their camera gear expenditures differently, but each piece of camera gear has it's technical limitations.