Looking at your cake, I probably would have dab them or the spot where you wanted to put them with a tiny bit of gel with a paint brush. Nice job BTW.
You can also use the edible glue made with cmc also I love it!!!
I usually slightly press in the fondant with the small side of a ball tool, then glue them with edible glue. They never roll out any longer!
The advantage of this method is that you can also put the pearls on the side of the cake with no risk of them falling of and it´s much easier to space them out evenly since you are first "drawing" the holes with the ball tool. When you work on a big cake, make sure you work fast enough so that the fondant does not dry, otherwise it will crack when you press in with the ball tool.
I attach with piping gel, I also use the small end of my ball tall to indent when place them on the sides. This gives the dragee a larger surface area to adhere to. If placing them on the top of the cake, I would skip that step and just use piping gel.
Thanks for all of the helpful answers. I have purchased piping gel and can't wait to try it!
Make a shallow hole with the tip of piping nozzle (choose the same or slightly larger than dragée diameter), with the point of the nozzle take out the small off-cut, put a dab of glue or piping gel inside the hole and press the dragée slightly inside. Works so well on sides of the cake.