Double Loop Stitch in duplicate knitting

I’m making a Christmas sweater for my dd. It is charcoal gray in worsted, with a Santa Claus face on the front.

Since I prefer circular needles, I opted to use duplicate stitch rather than trying to determine how to knit it in. Now that I’m up to the armpits, I’m afraid it may be too stiff!!

Also, I just viewed Amy’s video on double loop stitch and think this would make a wonderful beard. Is it posible to do this as a duplicate stitch?

Thanks. Y’all are such a great help!