I suggest that these turn out beautifully on 16 count aida! You can pick a light tan, or look at the gorgeous colors available from picturethisplus.com
Yes, there is beading and they are listed at the end of the supply list, after the white DMC floss. There are two braids suggested, as well...one at the beginnng of the supplies amd one at the end with the beads.
I have chosen to use colored fabric for my mermaids. If they are green, I use the blues in fabrics and if they are bluer, I pick greener water-looking fabric. Play with it! You can do whatever you like.
Don't forget to add 6 inches to the heighth and width for framing!

I am not an employee of ECS, just a stitcher who saw your questions in this chat group.

I have done this particular patter and I did it on a pale green aida - it is a beautiful pattern as are most of the Mirabella patterns