There is no XP cost for Humanity, as this stat is meant to fluctuate as your character struggles to maintain it -- this is a major theme of the Vampire sphere! However, appropriate justification must be given as to why your character's Humanity moves in one way or the other before any modifications to the +sheet are made.
PC Ghouls are allowed, but require the approval from both the Vampire Wiz and the Mortal Wiz.
All Blood Bonds must be noted by Staff or they are considered not to exist.
Vampires can learn non-clan disciplines, but there must be suitable justification. A vampire can learn either through RP with another player or through NPC interaction, but for the latter they must have a relationship with that NPC. And, of course, if vampires are caught teaching restricted disciplines (e.g. a Camarilla Gangrel teaching Protean), there may be consequences!
When using a long-term discipline effect, such as Presence or Dementate, a vampire may affect a player character for no more than 1 IC month, even if more successes are rolled