Well Also; Welcome to LQ!
I can help you 2 of those questions...
Create a Ubunutu (or other simple to use) installation that can:
a) Be booted in it's own right from portable USB HDD (can't be only OS so already setup to multiboot and doing it from a Live ISO).
b) Can be booted from WITHIN Windows as a window (QEMU?)
c) Can be loaded from WITHIN Windows as a bar (Pubuntu style)
a) is pretty easy; but how do you wanna do it?
if booting from iso-on-usb with grub2 you can have multiple *buntu's on there
and )b is also doable
with PQemu Portable-Qemu
it runs from a folder, usb, cd, etc
and you can make virtual qemu-img's and connect them like drives using Grub
so, I can expand on it if you wish?