Still think it's a family member
Holy Knights seem like "public figures"
Depends, I have a few theories if Figarland exists:
1. You are right, there is a Figarland member thats not Shanks. From this either Shanks supports this character or is against them, but the fact that he visited the Gorosei makes it conspicuous
2. Shanks is one, but is not "outwardly" one. His role is of a pirates.
I think in either fashion, it still paints the odd question of where his allegiances lie.