addressing invitation envelopes

So I'm getting ready to address my envelopes, and I think I'm OK with the basic formats for the usuals:

Mr. and Mrs. John Smith (married couple)

Mr. John Smith
Ms. Jane Doe (unmarried, cohabiting couple)

Mrs. Mary Smith (single addressee)

What about a family? My cousins and her children area all invited. What should be on the outer envelope?:

The Smith Family
Mr. and Mrs. John Smith (parents)

I plan on including all of my cousins' names on the inner envelope (John, Mary, Jane, and Julie)

for a single woman I would put Ms. instead of Mrs.

Also, for families I put 'The Smith Family'

I have also seen 'Mr. & Mrs. John Smith & Family'

Thanks! I really liked 'The Smith Family' and I was hoping that was OK to use.

And yes, I do plan on using Ms. for a single woman. I wrote 'single addresses' meaning one name on the invitation - I wrote 'Mrs. Mary Smith' thinking of my widowed grandmother.