Remember that you cannot use Vicissitude or Obfuscate to disguise yourself as someone you are not familiar with, and you cannot copy a copy.
So if Carlos spends less than 5 min in his true form (such as at the last game) then you cannot mask as Carlos.
Also as the masked face of Carlos is a disguise then it cannot be used as the source for familiarity.
Anyone who is familiar with Carlos will automatically be able to spot someone attempting to disguise themselves as Carlos.
Applicable to other characters with obfuscate etc under license from Carlos for the appropriate fees.
Secondly - when I was considering other char choices for the reset STs advised me that any use of Vicissitude in a Camarilla setting would get the user killed similar to that of infernalists. Limited to no questions required, if you use V you are sabbat and get killed.
Do STs stand by this setting rule/mechanic/fluff?
… asking for a friend of course.