Puzzle Giveaway: Sequence (Music makes the world go round)

So, you like music, but want an adventure too? Scale the tower, rescue the princess, get all the treasure, that sort of thing? Well, seems you are in the right place then.
But of course I can't just let you wander in there all carefree. Would not be much fun if the hero just dies on the first song, now would it?
Therefore you need to pass a little test. Nothing too taxing, I'm sure. If you like music you'll know all this already. After that, well, we'll see how it works out for you.
You have until sunday noon to solve it. I'm sure you can do it much faster.

1) Fourth note of the cromatic scale (starting on the middle C)
2) ♯, ♭ and ♮ (major)
3) A round, chinese kind of lute (minor)
4) Four-note scale (minor)
5) Which fret do you need to play an A on the 3rd string of a bass guitar

Bonus Question for extra credit: Which instrument is this?