Mosshill house & estate was located in Corkeenagh townland, which is in Cloonaff/Cloncraff civil parish Co. Roscommon. You can see the property on the Historic OSI maps on GeoHive, location links on GeoHive do not work correctly on IrelandXO system - to view launch the GeoHive map viewer, select Data Catalogue/Base Information and Mapping on the top left, then tock the 'Historic 6" Map' options. Paste the following ITM coordinates in the search box - 596077, 786494 and press enter.
Google maps also show the area, the location indicated as Mosshill is in the north west of the townland.
The Catholic parish for the area would have been Aughrim aka 'Kilmore and Clonaff/Aughrim and Cloonaff etc...', and the parish has baptism & marriage records back to abt 1816, there are some McLoughlins in the Catholic records, but no sign of a Patrick baptised in exactly 1836 - it's not unusual for ages and dates of birth to be inaccurate in secondary sources. A slightly wider search of the other Co. Roscommon RC parishes between 1834 and 1838 shows about 6 Patrick McLaughlin/McLoughlin/Loughan baptisms.
Do you have approximate years of birth for the other children you mentioned ?
To trace a household that arrived at Toberpatrick townland after Griffith's Valuation you would need to search the Valuation Books aka Cancelled Land books which continue on from the primary valuation using the same format.. These have held by the Valuation Office in Dublin City - these records are not available online. The Valuation Office also hold maps showing the location of the properties Providing one of your McLaughlin family was the principal occupant or leaseholder they should show up.