Heres some of my index for Allens in Comber parish in case it helps you a little but not on the burials. You may know them all but here goes in case you dont. Some References will be from Ros davies website, which she protects from commercial use, visit it for more information anyway.
http://freepages.genealogy.rootsweb.com/~rosdavies/Allan, John, Comber, T/761/19, See
http://Http://www.proni.gov.uk/freeholdersAllen, Agnes, High Street Comber, Down: North, Comber, The Square, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, Anne, Tullyhubbert, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, Catherine A, The Square Comber, Down: North, Comber, The Square and Houses, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, David, Moneyreagh, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, David, Tullyhubbert, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, David. Comber Husband Of Mary Cochran; Father Of James B. 4 Apr 1866 & Isabella Maria B. 3 Oct 1868 & William Robert B. 27 Apr 1870 CR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, George William Graham, Unicarral Comber Co Down, Down: North, Comber, The Square, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, George, Mount, Alexander, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, George, Townparks, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, George, Trooperfield, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, Grace, High Street Comber, Down: North, Comber, 1st Presbyterian Church, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, Henry. Comber Of Ballystockart; A Miller; B.C. 1820 See ReseArcher Listed RD , Roll Call Johnburns ‘At’ Telus.Net
Allen, J. Dr J. Allen . Comber Medical Practice Established 1797, Supported By 250 Patients In 1836; Part Proprietor Of Ringneil Townland In Tullynakill In 1836 V7 P 34 , 122 OSM, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, James G., Steam Roller Proprietor , See Inhabitants Street Directory Extract In OS Comber 1900 Sheet 37, Godfrey Ed
Allen, James Graham, Comber, Down: North, Comber, Square, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, James. Comber Husband Of Agnes Allen; Father Of Robert James B. 30 Nov 1868 CR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, John, Ballyloughan, D/654/A3/1X, See
http://Http://www.proni.gov.uk/freeholdersAllen, John, Comber, D/654/A3/1N, See
http://Http://www.proni.gov.uk/freeholdersAllen, John, Comber, D/654/A3/1Q, See
http://Http://www.proni.gov.uk/freeholdersAllen, John, Comber, T/761/20, See
http://Http://www.proni.gov.uk/freeholdersAllen, John,, Jr., Tullyhubbert, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, John,, Sr., Tullyhubbert, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, John,,. Comber Husband Of Sarah Mckibbin; Father Of Jane B. 6 May 1866 CR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, Lizzie, Mill Street Comber, Down: North, Comber, 1st Presbyterian Church, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, Margaret Jane. Miss Margaret Jane Allen . Comber Wife Of Samuel Burgess; Mother Of John Allen Burgess B. 1874 CR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, Mary . Miss Mary Allen . Comber Wife Of Samuel Conkey; Mother Of Eliza Jane B. 1865 & Rosanna B. 1868 CR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, Mary, Castle Street Comber, Down: North, Comber, 1st Presbyterian Church, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, Mrs., Unicarville, See Inhabitants Street Directory Extract In OS Comber 1900 Sheet 37, Godfrey Ed
Allen, Phebe, Unicawal Comber, Down: North, Comber, The Square, 1912 see
http://www.proni.gov.uk/covenanters,
Allen, Rep., James, Ballyaltikilligan, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, Rep., James, Bridge, Street,, Com’, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, Susan, Castle, Lane,, Com’, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Allen, Thomas, Tullyhubbert, D/654/A3/1S, See
http://Http://www.proni.gov.uk/freeholdersAllen, William .Comber Area A Farmer; Father Of Mrs. Eliza Robinson, A Widow, Who Married John Shaw In 1875 At Linenhall Presbyterian Church, Belfast PR, See
http://freepages.genealogy.rootsweb.com/~rosdavies/Allen, William, Tullyhubbert, , Householder 1863, 4 Ie Griffiths V See
http://Http://www.failteromhat.com/Good luck. Jim
ps Have you tried Clarke gravestones of Co Down a series probably published by Ulster Historical Foundation. The UHF also has databases that include Allen surnames.