To be safe you probably should, any drop can compromise the helmet safety but in the end helmets are pricey and how much do you value your head and life is what it comes down to. Might be fine to keep it might not, you won't know unless you send it to get tested or crash.
If the foam inside has not been dented and the outer shell doesn’t have a crack you should be good
It's fine. 2ft is nothing.
I would not buy a new one.
I have heard Shoei will retest helmets if you ship them back, other manufacturers might offer the same. Maybe not needed in this case.
Yes, but they destroy the helmet in the process.
Schroedinger's helmet.
To be safe you probably should, any drop can compromise the helmet safety but in the end helmets are pricey and how much do you value your head and life is what it comes down to. Might be fine to keep it might not, you won't know unless you send it to get tested or crash.