dammit, i don't know that much
I have no clue about the E-Reader, cuz i don't own 1.
I heard that the Tilt n Tumble doesn't work with it since the screen is at an angle, but again, I don't have it and don't know.
There's a jack specifically for the link cable, though i don't know about the gamecube action, but it might use the same jack.
and yes it's fine without the headphone jack, the volume control is a sliding bar instead of a wheel, and it works fine and sounds good.