I was of the impression that we are supposed to write our guests' birth/full name on the outer envelope of our wedding invitations. How much did you push to find out names that they don't use? I feel like I'm already asking my parents and grandparents to help out so much with the many addresses and correct titles to use. It's been such a task trying to collect them. Most of these people I'm asking about are my extended family/in-laws that I currently have no way to contact directly, so I am at a loss there. The other few I think care so little for the name that I'm not sure they're worth asking, and possibly annoying, them over.
Is it really necessary to bug people to find out a person's formal name when I know they don't ever use it? I'm not talking about casual, fun nicknames. Their parents gave them these formal names, and from the start they always planned to refer to them otherwise. I want to be etiquette friendly, but is there a point where it's too much?