As ruled by DMs multiple times disguises are not supported in EfU. The Spymaster perk provides a disguise kit which has no real enforcement. It exists only as a trap option for players. Due to the confliction here, it would probably be best if the perk was simply removed.
Edit: After discussion with the team, the use of the disguise from Spymaster is indeed illegitimate of a 'true disguise'. However players may choose to use them with flavor as they please.