I give up: what is a fake gas valve?
Regarding the toilet, plumbers putty may stain some types of flooring, and will itself get stained and ugly.
Plaster of paris seems like overkill, and messy.
A tub/tile rated caulk of a color to complement the floor, or white to blend with the toilet, is your best choice.
None of these is meant to compensate a toilet which rocks. If the floor is uneven, you must fix the toilet with shims first. Only then apply the caulk as a cosmetic measure.