Just catching up, hard to stay current.
FWIW, it is our belief that makes us members of the family. IOW, first you must believe THE GOSPEL and have faith in Jesus to be a member of this family.
I fully agree that members of this family are found in all types of assemblies.
You are not in a family because of what you believe..
Its totally who you are that determines physical relationship..
And according to Jesus, spiritual relationship..
"You MUST be born again" -Jesus
NOT you "must" be enlightened intellectually..
Nicodemus was unclear also, as you are(seem to be)..
Some people are "thick".. (like Peter or Thomas)..
Its not what you believe its who you are that counts..
Belief is a nebulous thing.. sophistry and semantics..
WHO ARE YOU?.. Is the question...