http://www.failteromhat.comIn the civil parish of Bangor in 1863, using the spelling of McCullough we have 27 entries and for Kelly 16 entries some are as landlord etc Listed in Griffiths valuation see
http://www.askaboutireland.ie/griffith-valuation/index however a short cut is take the county index that shows townlands etc see
http://www.failteromhat.com Kelly Anne Ballyfree Bangor Down
Mc Cullagh James Ballymaconnell Bangor Down
Mc Cullagh Hugh Ballysallagh Major Bangor Down
Mc Cullagh Edward Ballysallagh Minor Bangor Down
Mc Cullagh Thomas S. Ballyvarnet Bangor Down
Mc Cullagh Thomas S. Corporation Bangor Down
Kelly Thomas Cotton Bangor Down
Mc Cullough Samuel Crawfordsburn,(Ballymullan) Bangor Down
Mc Cullagh Robert Gransha Bangor Down
Mc Cullagh John Gransha Bangor Down
Mc Cullagh Thomas Gransha Bangor Down
Mc Cullagh James Gransha Bangor Down
Kelly Eliza Main Street,Groomsport Bangor Down
Mc Cullagh Thomas Portavoe Bangor Down
Mc Cullagh Thomas S. Rathgill Bangor Down
Mc Cullagh Thomas S. Rathgill Bangor Down
Mc Cullough Anne Upper Row,Groomsport Bangor Down
Mc Cullough John Village of Conlig Bangor Down
sadly I found no trace of Crosby in Griffiths in Bangor. So finally spotting a match by close location I am hoping the luck of the irish might suggest the they have something to do with Groomsport in the civil parish of Bangor, who population did use Bangor Abbey for some burials
The irish times ancestry page , recently changed to
https://www.johngrenham.com gives a short but important list of spelling variants found which is far from the two spellings I have only used, my time ran out and a subscription was suggested. if you are not used to spelling variants , its all part of the norm including enumerators background.
The Tithes Applotment books are not complete for Bangor it only includes a townland or two see
http://www.irishgenealogyhub.com/down/tithe-applotment-books/bangor-parish.php#.V1HW2leoc5R The originals are in the PRONI Belfast, Parts might exist if there are Bangor papers etc at PRONI
if you haven’t used
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies m, I strongly advise you to exhaust it
I had a peep fpr Crosby and started to find Bangor coming up in the parish column
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies/SURNAMES/C/CrocCrot.htm#crorgood luck onwards