You don't need CAN for a Mk4 Ibiza.

Whether it works or not, who knows...!

It won't act as a dongle to activate the registered-only facilities of vag-com though, you'll still have to register vag-com or buy a pukka vag-com cable for that (which is worth every penny IMHO).
 
where do you get those from?

are there different levels of vagcom hardware?

i have no idea :p