I also chose not to use the metal buckles for the birthday onesies, simply because the boys are bigger now and would have been tempted to try to pull the buckles off of the shirt.
Lastly, because my boys are bigger now than they were at Christmas, and it has become their very nature to destroy anything they can get their hands on, I found that hot glue was better than the heat-n-bond to get the suspenders to stick to the shirt. For whatever reason, the heat-n-bond with the ribbon stuck to the shirt, but when little toddler hands tried to pull the ribbon off, the ribbon came off. A quick fix with the hot glue gun, and it became toddler proof. Again, this is a no-sew version and this really was just a photo prop for me. If you are wanting something long term or are looking to create something to sell, then I recommend using a sewing machine and forgoing the no-sew version. This mama is not a seamstress. I'm just crafty, so the cheap and quick no-sew version worked just fine for me.