This is a very nice way to shape the neck and shoulder for a baby sweater because it leaves plenty of room at the neck to get the sweater on and off without annoying the baby. The ~14sts that you're holding out will indeed become part of the neckband along with sts from the front and perhaps some sts that are picked up on the neck edge of the shoulders. I don't see how the sts would come off the stitch holder but if they do, just put them back on. You're the boss. I sometimes use a length of scrap yarn as a stitch holder because it's more flexible. If you knot the ends of the scrap yarn, the sts will have nowhere to go.
Love to see a picture of the finished sweater if you'd care to post one.