So what were the things to note; I used Shapewell instead of interfacing for the headbands and this worked really with regard to holding their shape.
Next time I would probably make the star a little smaller, but I had that template on hand so went with it.
I put the stars on using Heat 'n' Bond which I had never used before but found it worked well, though takes a while to fuse.
I also interfaced both fabrics on the cape where the snaps were going to be for extra support as I figured they might get some wear and tear.
The smallest loved hers so much she left it on all day at the party and wore it to my basketball game tonight!
And Miss L had a lovely time watching it fly out behind her on the swing today, so the late night was, as always, worth the effort!