Suggest you use FindMyPast for most of the BMD records as it has the Welsh records and some of the Shropshire ones, though some errors in the indexing. My parish record booklets were purchased from Clwyd FHS.
Denbighshire records would be your main source but also Shropshire (part of Llansilin was in Shropshire!) and Montgomeryshire.
Familysearch has links to many of these records on FindMyPast, so that would be a possible first search.
Wills and newspapers are online on the National Library of Wales site.
If you do have any queries, just ask

Gadget