That'll attract the ants...Not sure about the coloured lather but can't help wonder if there is an element to actually using lather that lets you see what bits you have shaved or haven't shaved. Sort of like that pink ceiling paint that turns white so you can make sure that you have painted the entire ceiling and not missed bits.
And as for using vegemite as a shave cream - surely you would use it as a balm or after shave. I did see one Kevy Shaves Youtube video where he actually used Irn-Bru as an after shave!!!!
cheers
Andrew