It looks as though eldest daughter Elizabeth Cretney b.Isle of Man, Douglas, aged 17 was a Dom Servant unm in Toxteth Park Liverpool in the 1861 census.

Which leaves mother Elizabeth Cretney (remarried?), Cath/Jane bapt 3 Dec 1846 St Barnabas Douglas, and son John Joseph bapt St George Douglas 22 Aug.1848.

In the 1871 Liverpool census there is an Elizabeth aged 26 b.Douglas, wife of Peter McGoverin aged 43 Marine Store Dealer b.Ireland Sligo with their children Catherine E 2, & John Richd 6 mo., niece Catherine Whelan 4, all b.Liverpool, and (Peter's) brother-in-law John Cretney 22 sailor b.Isle of Man, Douglas.

Surname First name(s) District Vol Page
Marriages Mar quarter 1866
CRETNEY Elizabeth Liverpool 8b 25
MCGOVERAN Peter Liverpool 8b 25

Births Sep quarter 1868
MCGOVERN, Catherine Elizabeth W. Derby 8b 312
Births Dec quarter 1870:
McGovern, John Richard Liverpool 8b 77
Deaths Jun 1878:
McGOVERN John Richard [age] 1 Liverpool 8b 78
Deaths Sep 1878:
McGOVERN Catherine [age] 10 Liverpool 8b 146

In the 1881 census Elizabeth 35 is a widow at 57 Simpson St., Liverpool, with son John, 4, b.Liverpool.
Births Sep 1876:
McGOVERN John Liverpool 8b 92

I couldn't find John Joseph for certain again, but as a sailor he could have been anywhere.
Brian's IoM burials have: CRETNEY, John ag. 60 Braddan 25 Jun 1909 which could possibly be his if he returned to the IoM.
There was a John Cretney in the IoM of about the right age married to Esther Colvin in the 1881 & 1891 censuses, b. Douglas, Gen lab., in 1891, but born Jurby, farmer, in 1881.

No sign of Cath/Jane Cretney in 1861.

Sue