What kind of substrate do you have your KSB on now?

The ExoTerra Plantation Soil is basically the EcoEarth already expanded in a bag, so that is fine to use. I have an Apricot Albino Pacman and have never noticed any staining on him and I use the EcoEarth. That's just slightly weird?

If your Pac isn't eating all 3 of the crickets then I would remove the one that is left over so no harm comes to your frog. If left in too long the cricket may decide to chew on your pacman.

You won't be able to determine the sex of your PacMan for quite some time if it is only just a little larger then a quarter.