For the John & Elizabeth Morris part of your post, if I've got the right family on the 1881 census then they are living in Llansilin, Shropshire and the birthplaces are:-
John - Llanrhiadar, Denbighshire (probably Llanrhaeadr-ym-Mochnant which is close to Llansilin)
Elizabeth - Cynwyd, Meirionethshire (there is a Cynwyd just outside Corwen which used to be in Meirionethshire and now is in Clwyd)
Mary and James - both Llarmon, Denbighshire (probably Llanarmon Dyffryn Ceiriog which again is close to Llansilin)
So maybe their marriage would come under Corwen. There is a John Morris and Elizabeth Jones on the same page for Corwen in 1875. Could that be them? These are the BMD index details:-
Year: 1875
Quarter: Oct/Nov/Dec
Distrcit: Corwen
County: Denbighshire, Meirionethshire
Volume: 11b
Page: 683
Cheers,
Gwyn