Rosetta:
Welcome to Ireland Reaching Out!
Below are the 1823 marriage record and the 1830 baptismal record both in Killorglin RC parish. As you indicated the Mullanes lived in Sunhill which was likely a place name in Killorglin civil parish but was not made an official townland in 1851. I did not find any other baptismal records for children of Timothy and Mary. www.irishgenealogy.ie is a free Irish government site which has Co. Kerry church records. The Killorglin RC parish register is not online.
I could not find a Timothy Mullany baptismal record on www.irishgenealogy.ie There were a few Mary Slattery baptismal records although not in Killorglin. However, without knowing her parents names, you can't confirm a record.
Civil registration of deaths did not begin until 1864. I looked for death index records but did not locate a possible record.
I did look at the 1852 Griffiths Valuation head of household listing for Killorglin civil parish and there was a Timothy Mullowney on Mill Road likely in Killorglin town. Possibly this could be your Timothy Mullany?
Roger McDonnell
http://www.failteromhat.com/griffiths/kerry/killorglin.htm
Area - KERRY (RC) , Parish/Church/Congregation - KILLORGLIN
Marriage of TIMOTHY MULLANE of SUNHILL and MARY SLATTERY of NR on 2 November 1823
HusbandWifeNameTIMOTHY MULLANEMARY SLATTERYAddressSUNHILLNR
Witness 1GERALD DODDWitness 2JULIA MURPHY
NameDANIEL MULLANEDate of Birth21 November 1830 (BASED ON OTHER DATE INFORMATION)AddressSUNHILLFatherTIMOTHY MULLANEMotherMARY SLATTERY