I was just at my local quilt shop and now you can purchase a pen that you can write on your fabric, it comes in a variety of colors - Black is the color I have, I wrote my name a couple of times on the attached picture on white cotton, then ironed the second name and it disappeared without a trace.
You might want to ask your local quilt shop if they can get you one of these - it was $3 so very inexpensive, made by PILOT and called FRI X ION ball and it also says remove by friction - but the iron worked well for me, as you can see by the pictures
Also on one end of the pen there is like an eraser, so you could erase it if you were not close to your iron.
This pen would work really well for those type of templates.