Honorary Bridesmaids?

You can definitely invite people to the bachelorette party that aren't bridesmaids! I'm having a small wedding, so every single one of my friends coming to my wedding was invited to my bachelorette party.

I think whether or not it would be rude to have them has "honorary" bridesmaids depends entirely on your relationship with them and how well you know them and know what would upset them. I personally would just stop with the 4 BMs you've already picked and invite them to your bachelorette party, but in the end it will be up to you.

Sides don't have to be even.

The title "honourary bridesmaid" just indicates that you like some people better.

How old are these other ladies? Are any of them by any chance early teens, i.e., 13-16? If so, they could be junior bridesmaids. I had four regular bridesmaids and one junior bridesmaid, who was 12 at the time of our wedding. If they're all adults, though, there are plenty of ways for them to be involved without being bridesmaids. If they're coming from out of town, you should invite them to the rehearsal dinner, at which they could make speeches if they like. You can also have them help decorate your venue. That's what my husband's sisters did. None of them wanted to be bridesmaids (and I wouldn't have asked, anyway), but they still wanted to be involved, so they helped my mother-in-law set up the centerpieces while we started the pictures. Maybe you could have these extra friends of yours greet the vendors and show them where to go and what to do while you and the actual bridesmaids are getting ready and having your pictures taken.