Wedding color

It’s not normal, but you can’t prohibit your guests from wearing a color. Surely your guests will know they’re not in the wedding party since they won’t be standing next to you during the ceremony.

I think its okay. My color is Vintage Mauve and some of the women in my immediate family will be wearing something close to that color.
I think it will look good in pictures.

It’s an old school normal. Now people generally will avoid the wedding colors as to not step on anyone’s toes. But it’s really not a big deal, especially if the style is appropriate (as in wearing formal dresses to a black tie, etc). And they are probably not going to be in most of your pictures, so looking back you won’t even notice. While I can see why this is annoying, it’s a battle I would pass on. There’s bigger things to stress over.

It should be totally fine if they ended up wearing the same color as the BMs. It'll likely be very obvious who's in the bridal party!

It's actually the guests trying to compliment your wedding. I believe a guest that cares not to stand out too much on your wedding day is cool. As long as they're not in the bridesmaids gowns.