Yes I have a Scorp mother and we have the same problems as you...I think the nosiness is just a mother thing because I had to tell mine once that I am a very private person and if I want to share something with her I would. I am an adult and not a kid anymore.

As for getting along with other Libras, I never have a problem with it so maybe that also is more family based. Families feel they have more right to an opinion just because they are related....would certainly piss me off if they were over stepping the mark and it is easier to show your true feelings to another member of the family!