Yes top stitching is necessary. Just take it slow and easy and use a simple stright stitch. The fusing will hold but with baby stuff, you would want to do top stitching as well. Line ethe middle of the presser foot just to the inside edge of your desing and stitch right at the edge of each piece. BAck stitch one or two stitches when starting to anchor your stitching and then go all around each piece. Its not that hard. If it is necessary to turn the piece, leave the needle in the down position and lift the presser foot and turn until your needle will fall back on the applique. Just continue to stitch and turn until you have gone all the way around. AT that point take a few more stitches backwards before cutting the thread and everything should be secure.
The only alternative is to do needle turned applique, by hand, turning under the raw edge as you go. Top stitching by hand through heat n bond is not easy and a royal pain in my opinion.
Good luck and let us see pictures when you are done! :-)