I am one that does not quilt with white or neutrals, I either pick a color and go with it or use variegated thread, so I am used to the thread making a statement on the quilt. Your quilt colors are really pretty. I do not care for the purple. It distracts from the beauty of the fabrics. I would look for variegated with green and turquoise, or use any other color in the quilt if I was making it.

That being said, it is your quilt, you can see how it looks in person which is often completely different than on any computer picture. If it pleases your eye, go for it. If you look at it and you get the feeling it is off, try something else. I think you must not really care for it or you would not be asking for other opinions.

No matter what, with that stencil, and those fabrics, it will be gorgeous.

Good Luck!