Just curious (and how many)?
Not sure, since I was opening them blindly. But I counted around 6, I was more focused on corpses, logs, rocks, bodies, barrels though to make sure I don’t miss any secrets so i can’t tell you the exact number. Sorry
Yes there are 7 new one shot chests, some of them quest related.
So there are 7?
I was pretty thorough and only found 1, guess ill have to go look fore more.
Or are maybe some of those chests not literal chests so that Ive overlooked them?
I have some screenshots with some of them, and the map to go with them, but I haven’t found many so I haven’t gotten around to posting them anywhere yet. Hopefully soon, or someone beats me to it and I can be lazy. 
I found 5 so far in the wild.
Are two of the chests by the final boss considered one shot chests, or did I miss some?
The one in Ugdenbog, that spawns 3 hero ghosts, is that related to some future quest or is a one-shot?