A:Answer Yes, with a caveat. The right earbud will work without the left, the left will not (as far as I know) work without the right.
My understanding is that the right is the primary earbud and initiates the Bluetooth connection, the left earbud has a reserved Bluetooth connection to the right, and connects thru the right earbud. This being necessary for the synced sound.
That being said there might be some workaround to use the left by itself, but as I have never just wanted the left earbud I have not looked for one. I have, on occasion, used just the right.