Invite new friends?

I wouldn't B-List these girls. At this point, they'll know they are an afterthought, and that can be hurtful. I'm sure they don't expect an invitation since you weren't close friends when you sent the invitations out.

I would simply give the invitation face to face and explain that the list was made before you became close but express that since your friendship has grown you would love for her to be there. That way it's not hurtful that she wasn't invited. Especially if you guys have gotten close, she maybe upset if you don't invite her.

I also agree if you want them there I would give the invitation face to face. I think Joanne said it best. You weren't close when you made the guest list. You have gotten much closer since then. If that's someone that you really want there and it just so happens that the friendship has bloomed since then I personally don't see an issue. I feel like B list situations are rude in general but you aren't a fortune teller to know that a friendship would grow stronger.

If you want to invite them i say go for it. We had the same thing and invited the new friends late. Everyone came and had a great time. You didn't know them during your guest list creation and friendships happen. I think if you did it in person they would be honored to attend.