Jean,
I am doing a really extensive research deep dive into the 4 different John Skelly individuals.
1. John Skelly (1821), son of Edward Skelly and Margaret Quine
2. John Skelly (1821), in home of Robert Skelly the fisherman
3. John Skelly (1818), the servant in Castletown.
4. John Skelly (1815), who married Elizabeth Duke

I found a John Skelly from Braddan, born 1818, son of Thomas Skelly and Jane Kissack. Is it possible that this JS could be the servant?

Another question that I have, is it possible that JS1 and JS2 are the same person? Maybe he was visiting a relative on Queen Hithe Street in Castletown and got counted in the census twice?

I am really looking more and more at JS1. I have found several descendants from that particular family that are showing up as DNA connections. I have a questions for you. That family is located on a farm called Ballamona for several decades. After the father Edward Skelly dies, Margaret is found in a census on a farm called Moany Mooar. I wonder how she ended up there. Maybe a family member.

I feel like I am getting closer and closer to some revealing answers...