I wouldn't window-pane for this. I'd use Misty Fuse on the back of the fabric before cutting. Misty Fuse is a super lightweight double-sided fusible. Iron the pieces on the background as usual for fusible applique, then use your blanket stitch (or straight stitch near the edge, or zigzag, or decorative stitch) to secure the edges.
Regarding stabilization of the background fabric, what I do is *heavily* starch the background fabric before cutting. For this I use a 1:1 solution of Sta-Flo liquid laundry starch and water. My method is to "paint" the starch onto yardage until it is saturated, wait a few minutes to allow the starch to penetrate the fibers, toss in the dryer, then iron with steam.
However, if you are using a fusible, it may not be necessary to stabilize the background fabric with starch. I would try a block or two without the starch to see if you can get away without that step.
For machine applique using freezer paper and turned under edges, I use the Accuquilt to cut the freezer paper shapes. It really cuts down on the time involved for this step. Only some of their shapes are useful for this purpose, but the orange peel would be one of them if you prefer turned-under edges.