[X] Write in, Plan Viser!
-[X] Had you not been what you are, you'd have joined in a heartbeat. As it was, they can likely see well, what you do. Joining directly would have implications on many fronts. Instead, would they be willing to accept you as an aid, possible protector, sorta kinda joined wink wink nudge nudge. Basically you like them lots, but you don't want them to be overwhelmed by your official presence.
-[X] Lydia is naturally someone different though, and she has her own voice! She also has your very complete support.
[X] Yes, join the Order of the Cauldron -[X] As an associated member? Explain how various obligations might keep both of you from the meetings at times.