There were two McCreanney families in Douglas at that time. No. 1 on your list, William, who married Jane Ward ,was the son of William and Mary Ann (Moore). They lived at 18 Cattle Market St. and had nine children, all baptised at St Mary's R.C. Church Hill St.

William 1868 (no birth date)

Mary Jane 19 Sep 1869 (no birth date)

Francis 19 Sep 1869 (no birth date)

Jane 19 Sep 1869 (no birth date)

Mary 19 Sep 1869 (no birth date)

Patrick 17 Mar. 1870 bapt. 20 Mar. 1870
(my pat. g. grandfather James McCartin was his godparent)

Mary 30 Sep 1871 bapt 8 Oct 1871
(g.p's William McCreanney & Jane Carvel)

Margaret Jane 30 Oct 1873
(my paternal g. aunt Margaret McCartin was her godparent)

William 2 Dec 1875 bapt. 13 Dec. 1875
(godparents Daniel Murray & Mary Ellen Clelland)

When William, son William McCreanney & Mary Ann (Moore) & Jane dau of John Ward married, their witnesses were William & Elizabeth Berry.

Weddings 2. & 3. David Alexander & Charles were sons of John McCranney & Margaret (Dollinson) their children were also baptised at St Mary's. I don't know if the families were related, they don't appear to have been sponsors for each others children.

William John 20 Ap 1871 bapt 21 May 1871
(godparents Francis & Ellen Todd)

David 1 Jun 1872 bapt 12 Jun 1872
(g.p. Jane Smith)

Hugh18 Oct 1874 bapt 18 Oct 1874 (may be my error in copying dates)
(g.p's John Connor & Mary Ellen Clenand)

Charles Aloysius 16 Nov 1877 bapt 18 Nov 1877 (as register is in Latin, Aloysius could have been nearest they could get to Alexander)
(g.p's Thomas Fitzsimmons & Mary Ann Farquhar)

John James 27 Jan 1880 bapt 30 Jan 1880
(g.p. Bridget McVeigh)

Ann Jane 9 Mar 1881 bapt 13 Mar 1881
(g.p. Bridget McVeigh)

When David A. son of John McCreanney of Fort St. Douglas married Emily, dau of Francis McAlearney & Ellen (Cairns), 5 Hanover St Douglas, their witnesses were William Saunders & Bella Mc Larney.

Charles, son of John McAlearney & Ellen (Cairns) was living at Sunnyside, Glencrutchery Rd Douglas when he married Catherine dau. of Francis Fitzspatrick of 45 Duke St Douglas. Their witnesses were Hugh Fitzpatrick & Elizabeth Lynch.

Can't help with any info. of anyone related to these families, but I'll ask around.
Hope this helps and I haven't made too many mistakes. Marie Radcliffe