Possibly not really relevant to your current research but relevant link in John Roberts' ancestry - David his brother remained at Pyrse and married and was with children by 1871:http://www.genuki.org.uk/big/wal/MER/Llanuwchllyn/1871.html
The Richards of Brynmelyn and Roberts of Pyrse lived within a few miles of each other.
Llanfor is approximately 7 miles from Llanuwchllyn with Llanfor only a mile from Bala:http://www.visitbala.org/history-of-bala/http://www.roman-britain.org/places/llanfor.htmhttp://en.wikipedia.org/wiki/Llanuwchllyn
You might find the above attachments useful.
Hope this helps