Should I go ahead and get inexpensive BM jewelry?

So I got my bridesmaids a diamond and gold circle neklace, and I am going to put it in an engraved photo frame, with a little book about friendship etc..

My question is, since I don't want them to wear necklaces for the wedding (everyone has different dress and different necklines) Should I go ahead and get them each a pair of earrings to wear with the dresses, or just let them wear what they want? I just hate for anyone to go out and spend more money on earrings.

What would you rather do?

Wear what you have?

Or have bride pick something to go with dresses?

I think the gift you're giving them already is enough - it sounds really nice.
Unless you want them all to be wearing the same thing, you don't need to get them all earrings as well.