well the Malew Looneys were there + paying rent! in 1639 - the lib assed goes back to 1511/1515! - there is another Lowney entry in the Malew intacks for a Tho Lowney but I can't find him in the 1686 lib assed of which I've got a copy but there is a decade of Lib vas still to do (1661-1670) so possibly his disappearance might be noted - I'll look at the 1623-1654 lib vas (which after 1630 is quite readable and the filming is generally quite good whereas the 1656-1699 book is badly filmed in sections.
We know that one Tho moved into Castletown in mid 1680's
There are Lowneys in 1607 in Lonan abbeylands - cottages in Kk Lonan John McLowny pays 8d, Patrick Lowny 3s 8d + another 8d, Dannold Lowny 6d - all these can be seen in the table of farmers in Abbey lands in Kk Lonan
I wonder if John Mc Lowney is the progenitor ?
Lib Mon is still on my list to do but will look at post 1640's next week when back on Island