I can't help but think that if I was visually impaired to some degree and attending the wedding of a neighbor, I would still take my place in a middle-to-back row in the church (or wherever). There are plenty of places where you can't see much of what's going on in front unless you're in the first 5 rows anyway, so I may not be any worse off than everyone else attending. If I wasn't a close family friend or relative I wouldn't want to take a place in a front row that should belong to someone closer. I'd could still enjoy seeing the bride pass as she walks up the aisle, still enjoy the music/vows/speaking, and still enjoy the reception afterwards where I would get my chance to see the HC up close and in person. I would never want to act so special as to think I belong in the first 3 rows unless I was offered one of those seats, and knew my relationship warranted the honor.
I also have to wonder if the vocal neighbor was using her companion's impairment to procure a place of honor for herself in the seating. Her other behavior sure suggests that she thinks pretty highly of herself, and not so much of others.