Only the active Pokemon can be affected by a status condition. It is possible to have a Pokemon be effected by burn, poison, and one of the other conditions at one time, but they cannot be in any way be asleep, paralyzed, or confused simultaneously -those 3 conditions cannot stack. You can use a poison and a burn marker to indicate those things, so they stand separate. When you sleep, paralyze, or confuse, the Pokemon card must be rotated a certain way to indicate that status, and you can only have it rotated one one way. If a Pokemon is affected by one of those 3, and an attack or effect does another, the new affect takes place of the old one.