The color in the name generally notes the color of the hypo. Green hypos look greenish....yellow hypos have a yellowish tint....etc. It is pretty simple actually.

Desert ghosts are the rarest. All the others are pretty common. Compatability depends on the line, but most hypos are compatable...it is a good reason to purchase from an established breeder who has breed their hypos into other lines and ask them those kinda questions about their particular animals.