Thank you! No I didnt use skeleton. I am quite new with Synfig. However, I thought of using the skeleton at first, but the move didnt appear like a real bellydance move that it must be. The reason is that the move is not just created by moving the bones, but also stretching or contracting the muscles.
I didnt use the loop as well becsuse eventhough the move is repeated, I changed slightly other parts like facial expression for a more natural look.
The link I didnt use too. I used mirror in the snake arm video only.
Again, It is not yet a month that I started learn animation. I dont know if there are other features in Synfig that can make my video making easier. I hope that I learn while I am working.