Hi Donna,

As confusing as it sometimes gets, I believe we are talking about 2 different families.
You wrote:
1851 Ballaugh Census - Distgrict 1 Page 20 #79 - Ballakinnag:
Mary Killip Head widow age 54 annuitant born Ballaugh
Jane Killip daughter age 17 Dressmaker born Ballaugh.

In 1851, your Mary is a widow.
In 1851, my John & Mary are both living, and they have their grandson, 4 year old John Stowell in their house (see below).

Below, is my family with some of the sources I've used to arrive at my conclusion:

From FHL film 0106727
Registry of Deeds, Official Copy. Parish Register of Lezayre
Baptisms:
1819- Jane, daughter of John Killip & Mary Corlett 2 June.
1821- # 168 Elizabeth, daughter of John Killip & Mary Corlet 25 December
1824- Ann daughter of John Killip and Mary Killip als Corlett 29 April

I have copies of those 3, but unfortunately, it was closing time and I had to leave. I’ll order the other 3 directly from Salt Lake City. I now know they are on the same film.

In the meantime, IGI patron submissions (which I don’t order) show the remaining girls:
- Mary Killip (female). Christening: 01 May 1826 Lezayre, Isle of Man. Parents: John Killip & Mary Corlett
- Margaret Killip (female). Christening: 02 Nov 1828 Lezayre, Isle of Man. Parents: John Killip & Mary Corlett
- Catherine Killip (female). Christening: 22 Dec 1830 Lezayre, Isle of Man. Parents: John Killip & Mary Corlett

From look-ups:
1841 Census - Lezayre, District 3, Page 10, Entry 44.
- John Killip; age 55;
- Marg (sic) Killip; age 50;
- Jane Killip; age 20;
- Elizabeth Killip; age 18
- (Ann Killip would fit in here)
- Mary Killip; age 15
- Margaret Killip; age 13
- Catherine Killip; age 13

1851 Census- Lezayre. District 1, Page 61, Entry 11.
- John Killip; age 64; born Lezayre; head
- Mary Killip; age 69; born Lezayre; wife (I think it should be age 59)
- Elizabeth Killip; age 29; born Lezayre; daughter
- Mary Killip; age 24; born Lezayre; daughter
- Catherine Killip; age 19; born Lezayre; daughter
- **John Stowell; age 4; born Lezayre; grandson

**John Stowell age 4 grandson, is the first-born son of John Stowell & Ann (Killip) below.

1851 Census- Lonan, District 4, Schedule 60, Glen Gawne
- John Stowell, head, married, 27, master miller employing 1 man, Lonan
- Ann, wife, married, 26, Lezayre
- Anne Jane, daughter, 2, Lezayre
- James, son, 2 days, Lonan
- William, brother, unmarried, 19, journeyman miller, Lonan

John Stowell died in Jan. 1855, his youngest daughter Catherine Margaret was baptized in June, posthumous, and his widow Ann (Killip) married Thomas Crellin in 1858.

Ann Jane Stowell (age 2 above) married Richard Pass.

Richard Pass was a witness for Elizabeth Killip’s will (1903). Other names found in the documentation are her sister Catherine Killip, niece Ann Jane (Stowell) Pass, & brother-in-law Philip Lace. The transcription is on Brian Lawson’s site.

In Catherine Killip’s will (1906) her beneficiaries were (her niece) Ann Jane Pass & (Catherine's sister) Mary Lace. This will is on Brian Lawson’s site.

Jane Killip (b.1819) married John Gawne
Elizabeth Killip (b.1821) never married. Died May 1903.
Ann Killip (b.1824) married John Stowell
Mary Killip (b.1826) married Philip Lace.
Margaret Killip (b.1828) no further information
Catherine Killip (b.1830) Died Jan. 1906. I believe she never married, even though she’s listed in her sister’s will as a widow, and in her own as a spinster. The census show her as unmarried

From 1871 onwards, every census including the 1901, shows the sisters Elizabeth & Catherine Killip living together. In 1881, Elizabeth is a farmer, so maybe she inherrited her father's property -- but I don't know that yet.
I don't have death/burial records or wills for their parents John Killip & Mary (Corlett) Killip.