slightly later than your direct connections but might be related if some family remained in Ireland...
just two Mellon households listed in Co. Wicklow that I see on Griffith's Valuation.
Peter Mellon, townland of Curranstown Lower near Arklow
leasing a house from John & Patrick Grannell - dated 1854
William Mellon, Bray town
owing a house and property freehold - dated 1852
see :
Mellon, Co. WicklowAlso quite a small number of Beatty entries - the first few appear as landlord/lessor for a number of properties around Redcross with a date of 1854.
Those listed as occupiers are :
Frederick Beatty, townland of Carrigroe, civil parish of Derrylossary
leasing 'House, office and land' and also 'Water / Lough Dan' (1854)
John Beatty, townland of Ballymoat, near Glenealy
leasing house office & garden (1854)
Thomas Beatty, Woodenbridge Row, Wicklow town
leasing a house (1854)
see :
Beatty, Co. WicklowThe transcripts, return images, and maps for Griffith's are available at
http://www.askaboutireland.ie/griffith-valuation/index.xmlShane