Above: smaller set.

The above is slightly larger than you specified as that seemed too small to contain the action of a number of dancers.  If you could be more specific as to how many people and how close they can be to the screen then it could be reduced to the smaller scale.
Also, was curious as to why you specified a grey wall for projection. To get the most efficient bounce from the projection a white wall would be better? unless there needs to be moments of grey without imagery?, or even the use of a rear projection screen to avoid the sharp angle of the projection would be better. With lens shift on the projector it may be possible to mount high and drop the image down without much keystone distortion and without hitting the dancers?
I would have to wait until monday/tues to get current pricing on the flooring.  This is a minimal amount of set so there should be no reason not to strike it from the stage at the end of the shoot.  Depending on the stage you book and the condition of the floor will determine if a sub-floor needs to be laid to get a flat surface for the high gloss  flooring.