I use Pellon fleece interfacing for my table runners, but it's only 45" wide so it would have to be pieced for a tablecloth. Just butt the edges and overcast it together. I love the way it adds body, but not a lot of thickness so a candle won't upset. For a tablecloth, I wouldn't use anything. It will drape if it has enough drop. A one layer tablecloth does, so why wouldn't a two layer, plus the weight of the seams and thread. On the other hand, a friend uses vintage quilts that have old cotton batting for tablecloths and they work fine. I would use the Pellon fleece just to smooth out the seams and give the quilting a little definition. I don't care for the fusible.
To make a round tablecloth, make the quilt pattern you want only don't worry about the corner blocks. Fold the top in quarters, tie a pencil tied to a string, hold one end of the string at the point of the folded quilt top and draw a line as you move the pencil. Cut on the line, unfold and you have a circular quilt top. The distance between the endpoint and the pencil needs to half the desired size of the cloth. Add a little extra to allow for quilting. I've done a newspaper pattern with the string and pencil, too.