If your Save the Date and/or Formal Invitation was addressed to you and your significant other, yes. If solely addressed to you, no.
No, not unless you're somehow related to the bride or groom.
No.
Yes.
Yes.
You can't handle the truth!
Ghostbusters!
No.
Who.
SPOILER ALERT! Gwyneth Paltrow's head.
Mountain.
Wind.
Dark.
Fish.
Time.