Okay, The list I am using must be incomplete with prayer beads, bosses or treaure chests cause I'm well ahead of you, many mini bosses and and treasure chests ahead and I just unlocked 18 VIT. I was on 15 VIT when I done the monk, how the hell did you manage 17 VIT? I'm bloody confused now as to what bosses but according to the list I have, I've done everything but a few headless bosses. By any chance did you pick up those and I don't want to spoil it, really well hidden prayer beads before the monk the ones you'd never find without a guide?
I'm going to have to sweep all areas again before I move on to what I assume is the final boss or at least the penultimate boss for me.
The prayer bead before the monk in the house was the only one I can recall in that area that I would consider really well hidden. I got the water mechanic and found one under the water shortly before that. I did feel pretty special finding that bead though.
I'm one bead away from 17 vitality now. I ended up playing a bit more and went back to ashina castle and collected most of the idols a second time. I fought a pretty tough mini-boss to get a bead at the great serpent shrine. He was tough as balls and I managed to get super lucky on my third attempt and he ended up doing the same moves multiple times in a row letting me posture break him.
I also fought the underwater headless. But when I go through an area I fully explore every possible part of the zones, walking along the edges of pretty much every path to look around for things. I've probably missed some stuff, but I have beaten every mini boss up until this point, and that's where a lot of my beads have come from. My achilles heel is that I have a bad memory, so I oftentimes forget to backtrack to areas when there is something I can't collect right away. Hoping to finish the game with all the beads, but we'll see.
Edit: Is there a way to check playtime? I have quite a lot of playtime due to how much I explore, and some of the trickiest fights have been with those mid-bosses. The three story pagoda mid-boss and lady butterfly are by far the fights I spent the most time on though.