Default false. If true, only picks from legal mons. If no legal mons are found (or there is 1, with doNotReturnLastAllowedMon = true), will return a mon that is not allowed.
Default false. If true, includes fainted mons.
Default false. If true, will never return the last unfainted pokemon in the party. Useful when this function is being used to determine what Pokemon to remove from the party (Don't want to remove last unfainted)
Will never remove the player's last non-fainted Pokemon (if they only have 1). Otherwise, picks a Pokemon completely at random and removes from the party