The Guardian Soul can be fed to Frampt for 10,000 souls.
Elizabeth's Mushroom can be fed to Frampt for 1,000 souls.
Using the Obsidian Greatsword's 2 handed strong attack consumes 50 durability per use.
Kalameet's breath attacks due not appear to be fire based. I used the the Black Knight Shield +5 for the fight and it definitely did not reduce blocked breath damage by 95%. It is more than likely concidered Magic damage. The BKS reduces magic by 25% and I would say that is much closer to the amount of damage it was blocking.
Anyway I hope this info is helpful and as of the time of this post , I did not see any of this info on the respective pages.