Yes, keyboards can be connected to Line 6 UX2 equipment, provided they have the appropriate output connections. The UX2 has line inputs that can accommodate various audio sources, including keyboards. You would typically use a 1/4-inch TRS or TS cable to connect the keyboard's output to the UX2's input. Ensure that the input settings are correctly configured in your audio software for optimal performance.
To complete Bloc 'n' Roll (aka Bloxorz)U = Up, D = Down, L = Left, R = Right, S = SpaceRx4, U, L, Dx3, Rx4, Ux2, L, Ux2, Lx3, D, R, U, Rx2, D, R, U, Lx3, Dx2, Lx3, Ux2, R, Ux2, L, D, R, U, R, D, L
The Line6 UX2 is compatible with ProTools 9. ProTools 8 and previous versions are only compatible with Avid hardware (Mbox and Digi interfaces).
The UX2 includes Ableton Live Lite 6 Studio Edition. It can record and mix tracks for you, however, most users upgrade from this bundled recording software to a more professional package if they want to get serious. The UX2 has 2 inputs, so it can record 2 instruments or 2 microphones at the same time. If you need to record a whole band at once, you'll need a hardware mixer to mix all the audio down to a 2-channel (stereo) mix.
No, since it doesn't have any inputs in it, so you can't even record with it. Check for something like Line6 UX2 or google for "recording interfaces"