The only really hard trophy is the one for Defeating the Queen. Its not that she is that hard, but you have to beat the depth 4 defiled Chalice (enemies are about as hard as NG+ but you have to do the whole thing with 1/2 hp) to get the chalice she is in. Its a real ball buster.

I used a guide to figure out how to get 2-3 of the weapons. The one is missable if you dont talk to Elaine (or whatever her name was) really early in the game. Only other thing that is missable(assuming you dont beat the final boss accidentally) is the True ending. 2 of the umbilical cords are not missable but I think you can miss the other 2 if you dont manage NPCs correctly.  

I found most youtube videos worthless for boss fights at least for the chalice dungeons(the only truly hard bosses). I think depending on the chalice you get the boss movesets differ. I would watch a guy use a tactic on a boss but when i tried it, it would not work because the boss behaved differently for me.

I would say at least 3 of the trophies require chalice play.

1. The Queen

2. The beast Claw (only found in chalice dungeons)

3. The precious blood gem (I have not found one in the game outside of chalices, but the 3rd boss of the depth 3 chalice drops one)

nice! im yet to finish demons souls.

It seems like devs are going easy on trophies this gen.

Believe me, I did both dungeons again (from top to bottom) and hit every wall in each room; I even checked the elevator walls and the ones by the lanterns, and used a shit load of shiny coins to mark all the rooms I had been on to show I had been there and hit all those walls.

I thought maybe a path opened up by some other means and people might know it, or maybe it was a algarithim goof because some of these are computer generated.

I plated Bloodborne as well, also have a Demons Souls Plat, a Dark Souls Plat and a Dark Souls 2 Plat. Im looking foward to platting Dark Souls 2 Scholar of the First Sin on my PS4 next.