If I understand it correctly myself, the headstone are just how many you can have active at any given time. The normal chalice dungeons don't change, they're always the same. You need the... hmmm... Root chalice? I think that's the name. The root chalice are the random ones, so every time you create a new root dungeon, it should be different (Unless you're really, really, REALLY unlucky I guess).
Someone let us know if I'm wrong though, been some time since I played now...
"If it's there, I have to use it". I feel like much of this boils down to that, and I think it's really stupid. Things in the game that are PURELY OPTIONAL to use that you don't like? Don't use them! Armor/weapon/whatever that you got from a pre-order that ruins the experience for you? Don't use it!
Personally I try to stay away from pre-ordering games that gives armor/weapons/whatever that makes the game easier or work as an otherwise shortcut. If I do pre-order the game anyhow, I just don't use it.
I had the saw cleaver. Put fire on it, ran up to him, smacked him. He teleported, I ran after him, kept smacking him. Never dodged, never cared. Suddenly he was dead. That was it... I thought that fight was easy as fuck, the spiders never did anything neither did the boss when you were close to him (He did some stuff, like a blast and some rolls or whatever, but they were easy to dodge/stay away from). And no, I didn't have "easy-mode" bug on.
Had a worse experience in the chalice dungeon though, but he still wasn't TOO hard. The limited space there made him a little harder, but that's it...
Maybe you're a bit underleveled? Do you use your blood-thingies that you pop for more blood? IDK, I did him on my first try and thought he was easy as fuck and, as many others, a refreshing change of pace.
I actually didn't find any of the bosses in BB to be particulary bad, most of the bosses I've seen other players complain on I did on my first try, and I'm not even close to being a "pro" at these games.
I never had to try a boss more than 5 times before I killed it though, but maybe I was overleveled? I popped ALL of the blood-thingies I found. I also used the saw cleaver all the way through the game, that weapon is prolly way better at this specific boss due to stagger.