All that is said before is true:
-Yes, you have to be part of an educational facility.
-Yes, you can buy a EDU-copy and register it. Registration is no different from full version. You should have to prove to the seller (retailer) that you have EDU-status, so the retailer can justify selling an EDU-copy: he has to answer to Steinberg about this, not you. Steinberg doesn't ask you for your EDU-status, they ask the retailer.
-Yes, if you do that but you are violating the EULA
-There are no EDU-priced updates, updates costs the same as full.
-Not sure if you can use EDU-versions commercially
So... just buy the full version ;-) , in the end it is a better investment (as also said before

)