Not absolutely sure I understand everything you wrote, but here's what I'm thinking.
I would use invisible thread to outline stitch all the interlocking borders.
Regarding the star, are you planning to stitch just the outline of the star? Or every triangle and block in the star? What I would do is quilt from one star point to another star point, so the inner squares would be quilted through.
I think it would look fine but, if you are concerned about puffing from SID, I would suggest changing the batting to something flatter such as Quilter's Dream Request cotton.