So I have a weird situation. My FH's parents are divorced. His father has been dating a woman for a while. FH and I have both met her and obviously she is invited. But we do not know her last name and FH's dad told us we didn't need it. I addressed the invite Mr. FH Dad First and Last Name and GF First Name because when I asked FH about it, he told me that his dad insisted we didn't need it. His dad filled out the RSVP with just his name but 2 attending. We know it is the same woman as they have been blowing up FH's phone for other things like meal request and hotel repeatedly even though those issue were resolved weeks ago.
The issue is we are going to have escort cards. Do I try again to get her last name or just put her first name and put her card right behind his? The thing is I don't care if it's her legal name or a preferred name, I just don't want people to think poorly of us or her to look singled out.