So in general adding The Immortal and Sticky Sea (yeah thats a thing) should be on the instance board, I agree on that to 100%.
For the Coin reward, 10 and 30 is way to high.
Alice Hard gives 6+16 Coins, so in total 22 and this is like the hardest current instance (which need a party).
I would rather say that normal gives like 6-8 Coins and hard 12-16
For your other suggestion, yes but maybe add the materials in other ways like Dim Weapons, drops from Episode Monster or something like that.
