Clonoe parish Catholic church has records back to 1806. Donaghenry parish (Stewartstown) dates from 1822, and Coalisland's Catholic church records date from 1861. I'm sure you might find more on your families by checking these records, or having a researcher check them, for any references to McKees and Canavans/Kavanaghs.
Hugh and Margaret's marriage record might reveal their fathers' names, depending on when they married. After 1864, Catholic marriages would be listed in civil registrations which required filling in the fathers' names. A "Hugh McKee" married in 1863 in Co. Tyrone, per indexes on the Irish World web site, as did "Margret Canevan" -- perhaps your ancestors. Would have to pay for full record but it's only 5 euros ($7-$8) if you'd like to get the abstract to find out.
I have a partial map of Gortnaglough townland in 1800s, obtained from PRONI files in Belfast. Will be glad to send you a photocopy if you'd like -- just contact me directly.
Ireland - Civil Birth Registrations: "Quarterly returns of births in Ireland, 1864-1955, with index to births, 1864-1921" -- Ireland. General Register Office. Available on LDS microfilm, and indexes (not complete) are on various web sites including Emerald Ancestors and Irish World.
Child - Margaret Jane McKEE Birth Date - 12 April 1868 Father - Hugh McKEE Mother - Margaret KAVANAGH Registration Location - Coalisland, Dungannon Civil District, Donaghenry parish, County Tyrone
Child - Ann McKEE Birth Date - 23 Oct 1872 Father - Hugh McKEE Mother- Margaret CANAVAN Registration Location - Coalisland, Dungannon Civil District, Donaghenry parish, County Tyrone
Let me know if I can help you with any other Co. Tyrone records.