Hi dottie dodge,
Nice to have you joining in the fun. If you have a good tight setting on the buttonhole stitch it will be fine if you used the steam a seam on the back of the appliqué pieces to place them. I use that stitch myself and it has plenty of coverage to the edges and looks great.
If you are for sure going to join in the fun, I will put you on the list so you don't miss out on the fun. Sign-ups close on the 30th and the deadline is only 2 weeks after that.