Post # 1
When you do the inner envelope do you write just "Suzy" or "Suzy & guest"?
Some people, I do not know who they will bring so I need to just have the "plus 1" listed as a"guest". Do I write this on the inner envelopes or not?
Post # 3
Yes, the inner envelope is used to tell who is invited. If you only put "Suzy" on the envelope, then traditionally, only she is invited.
Post # 4
Write it on the inner and leave the outer addressed solely to the recipient of the physical invite (aka your friend).
Post # 6
If possible, it is prefered that you put the name of the guest on the invite. Obviously, if you don’t know who she might take, "& Guest" is acceptable.