Also, I made a mistake with the year for Jane. You said she was 42 in 1861 according to the marriage certificate, which works out to 1819. Somehow I wrote 1809 on my note pad.
This now puts her at the end of the large family of Paul Fell/Fayle and Isabella Stevenson. The last one I could find on the IGI was John in 1817 at Braddan.