There are just so many many purple and white plicatas, some with very little difference between them. It is a very hard group to identify. Having been on that same garden trip as Gabe, I can say that it seems to me you would have to buy comparison plants to be sure, or take your bloom with you to a garden that grows a lot of them.
Do you have more shots of the third one? It is hard to tell the pattern on the standards.
