Just a couple of notes, I have not finished watching yet:
Firstly people who are extreme collectors may be inclined to purchase 2, one for sealed one for play.
Amiibo is the plural for amiibo, similar to how pokemon is the plural.
I believe the naming came from Japanese little friend, as you said, but I saw in an interview they wanted it to sound like amigo. I also believe the name could have been drawn from mii which could tie in with the mario kart functionalities.
And finally thanks for the vid, by your standards it may be late but for me its I preview
