buffs that are phrased:

- "if [unit] is in the field..."

- "when your chakra is more than..."

are pretty much permanent buffs that can't be removed, since even with the kamui barrier, you will still have your main character and chakra.

SB kage buffs are clearly stated to be permanent buffs. they can't be removed.

Fire main's shield mystery is none of the above, and can be cleared. Wind main's buff is also neither. It can be removed.

I haven't seen any discussion regarding water main, nor have i encoutered it myself, so i can't tell you canything about that.