The only thing you have said here that is true to a point is about the mice having a stronger smell.The rest is just plain INCORRECT .Where are you getting this info? A book, if so throw it in the garbage.I have kept my rodent colonies in the same room with my snakes( up to 13ft retic) and it never caused a issue.Maybe your doing something wrong if your having issues
i believe i was once told that mice smell stronger because the males "mark" their territory.
aka they go around piddling every few centimeters instead of just peeing in one corner.