[@Regitnui]

The problem with playing characters in characters is that if not done correctly, it will get tricky with the group dynamics.
Since currently both members accounted for are one person, yet there is no IC knowledge of them being the same person.
Therein both were assumed to be hired by the dwarf. And thus technically both would be owed 10 gp.
Thus Cas would be paid 20 gp total if the deception remains throughout the party.

You'll have to work out the details with the GM, but since our characters don't seem to know each other that well, no one knows Cas is behind both personas. Hence they should be treated as unique party members until otherwise discovered to be one changeling. At which depending on what happens when the deception is revealed, will be interesting...