hehe i remember having that summit and plagueborn..
I'd say that the inscribed staff is a safe merch, unless you want to spend a few hours to get 10-20k for it. The gloom I can see going upwards of, say... 75e? Get some more opinions first though
I'm thinking 100ish e for demons amber depending on market. 2 pts affects the value a lot, but wont really affect it much in actual game play.
No idea on summit or plague.
Staff is sellable. Might take a bit, but that's what the forums are for.