USB 1.1 devices on USB2.0

Just wondering a few question on usb1.1 and 2.0

I know usb1.1 is 12mbps and it's "shared bandwith" between all the devices attached. and usb2.0 is 400mbps

if I got a bunch of usb1.1 devices on a mobo with usb2.0. can I safely assume that the 400mbps of usb2.0 is shared with all my usb1.1 devices? mean with 400mbps, all my usb1.1 should be able to run in their full 12mbps capability?

will any of my usb1.1 run faster on a usb2.0 connection? ex. webcam, flashreader, scanner...