We do need to talk, but I think we all need to talk since we're bringing OG into this. He deserves to have his needs and wishes met, as much as we do.
Yup. Being the hinge person means nothing other than you are the person in common between the arms of the V.
Your hinge wants, needs, limits are not "higher" than the arm people's wants, needs and limits.
You all have to come up with your polyship's rights and responsibilities
and how you will play nice together and deal with things when they come up and there's conflict or things need calling into account.
Because life being life, things WILL come up.
Get the expectations laid out, and any assumptions cleared up now while emotional weather is relatively clear and you can set up your polyship framework so you can be in right relationship with each other. Be it in sunny days or through stormy times.