Hi Diane,
You certainly have been busy! Congratulations! I see you found quite a bit more info.

I don't have ancestry.com either but hopefully someone will pick up this message who does and see if they can find such a death.

I did find some Howe's on the "Ontario Cemetery Finding Aid" in Nipissing County who might be related.
HOWE Edwin Richard Boxwell Union Nipissing Chisholm NP-5856
HOWE Sarah E. (Towns) (w/o Edwin Richard) Boxwell Union Nipissing Chisholm NP-5856HOWE

And there are two Richard Howe's buried in Ontario but neither of them close to Rainy River. I doubt they are related but one never knows I suppose.
HOWE Richard Mount Pleasant Norfolk Walsingham South NR-92-73
HOWE Richard New Hope, Cambridge (Hespeler) (Section C,D,E,F) Waterloo Waterloo WW-4498
HOWE Richard Mount Pleasant Norfolk Walsingham South NR-92-73

Well, at least you have determined a bit more.
Bette