Alternative dyes for Gram staining
As you may have realized, crystal violet can be replaced by a lot of dyes since the ethanol will wash out the dye from the gram negative cells. Methylene blue is a nice choice - malachite green may also work.
A weak concentration of hydrochloric acid (3%) is also a possible replacement for the ethanol. A 3% HCl solution is used in the acid-fast stain but it may be too strong for non-acid fast cells. It would be worth testing it out and trying it to see if it could replace the ethanol step.