This may be a coincidence, but I have some information and looking for other info on Mowat / Marwick from Kirkwall, Orkney Isles.
May be able to help each other but the lineage is an illusive "eel" that disappears and resurfaces with annoying frequency. Some migrated to Winnipeg, MB as Selkirk Settlers, others with Hudson Bay.
I haven't done any research in many years now as too frustrating, but can dig up what has been done (old computer crashed and disks misplaced or gone) in some dusty files from the basement.
It would be interesting to tie some family together!
Till our paths cross,