Hello B.

I make the embroidery first. If you do the embroidery with all layers of material you'll see the back stiches of the design which is not very nice. I'm not familiar with the "flat flannel diapers" material you are using. I use regular cotton or terrycloth for bibs and burp cloths. If I use cotton I add some Tear-away" under the material and with terrycloth I also use the same stabiliser but I also add one layer of Clear and Melt (it looks like Saran wrap) over the terrycloth to prevent the stitches to go through the fibers. I also use a Jeans Needle to embroider the terrycloth.

Then I make the "sandwich" : top material + batting + back material just like we do in patchwork. Most of the time, I do some stitches (simple straight stitches will do ok but you can also use decoratives stitches) over those layers so they stay together (just the way we do in patchwork).

As for the batting, it is a matter of choice. I some time use polyester batting and sometimes cotton batting. For burp cloths I prefer polyester, it dries faster than cotton ...

I hope you understand what I have been writting .. I'm francophone so it is not always easy for me to explain in English.

A.