You may have any number of characters (humans or pokemon), assuming you keep them all reasonably active, but you may not set up a situation where one of your PC trainers owns one of your PC pokemon or where you trade between two or more PC trainers owned by you. Rare and evolved pokemon may be applied for, but the application must be excellent. The maturity-level and trustworthiness of the player will be taken into account, not just the application. If you whine at the staff about decisions, if you moan and cause trouble, your chances of successfully apping one of the rarer types will decrease.