Renting a Lens

My daughter has an upcoming vocal performance.  It's her last show with this particular group before heading off to college.  I'd like to up my photography of the event and wonder if renting a lens would be a good idea.  I like to use one lens that would allow me to capture some close up of the performers as well as group shots.  The group does quite a bit of dancing, so fast is important too. 


My current equipment:

Canon Mark 11 5D
Tamron 28-75 F2.8
Canon Zoom Lens EF 75-300 F4-5.6(came as part of a bundle package on my old camera)

Here are some pictures from the last show.  One big difference for this next show is that the background and floor are going to be white.  Which is honestly either going to be great because the lighting will be better or horrible because the white is going to wash everything out.  The kids are all wearing black/white clothing too.

cmpeterson.smugmug.com/VocalPoint-Show-Hop-Till-You-Drop-10-28-17/i-m6XbP2C

I'm very much a novice photographer...appreciate any lens recommendations/advice.

Thanks,
Cindi