Jinchuuriki are allowed to start with an additional ability or jutsu, so long as it pertains to the Bijuu inside them.
Jinchuuriki can not contact their Bijuu in any way until they have passed the Chuunin exams, failed the Chuunin exams twice but made it to the second stage both times, or have reached special conditions which a moderator decides. (Usually being brought to the brink of death in a fight)
Bijuu can be played by the Jinchuuriki user them self, or any staff member.
Most interactions with one's Bijuu must be moderated by a staff.