If you look on Brian's website, www.lawsons.ca you will see in his index of registered births, the birth dates of seven children to John Bills and Margaret Quayle in Douglas, including those you mention.

I found Margaret on the IGI. If you look on www.familysearch.org, choose Search, then International Genealogical Index, then type in father's name and mother's given name, select birth/baptism, British Isles, and Isle of Man. That will give you Margaret's baptism at St Barnabas and the birth dates of 3 sisters, no baptism place mentioned.