Hi James
Can find a marriage in IOM for these 2 on IGI or Lawson Micro site. As far as I can tell your Minnie Callow (with sister Ada) is not one of 2 Minnie Callows in our Callow family Tree but this IGI record might help: Not sure if you already know this birth/christening of Minnie Callow 1882:

Takem from the website-www.familysearch.org
"IGI Individual Record FamilySearch™ International Genealogical Index v5.0
British Isles
Minnie Callow Pedigree
Female
Event(s):
Birth: 19 MAR 1882 Ellerslie, Marown, Isle Of Man, England

Parents:
Father: James Callow Family
Mother: Isabella Bridson
Messages:
Extracted birth or christening record for the locality listed in the record. The source records are usually arranged chronologically by the birth or christening date. Source Information:
Batch No.: C009220"
Hope this helps
Shan Callow