1) Before it gets official I can consider it as "unknown". What is more - price tag is very risky criteria here. Products can be overprices and sometimes underpriced, yet still sounds like products at exact price points and actually perform better (or worse).
2) Openess is a similarity, nothing more, nothing less. Is not an argument for competition, class of sound is. And class of sound HD800 is quite high as for dynamic headphones.
3) Yes, but are branded as ones. You can use LCD, HD800 or even basic Lambdas for studio purposes too and no one can stop you, but then again: those are not branded and advertised by maker as suitable exactly for such purposes.
4) I personally couldn't care less about them and their posts. Only official informations and real user experience are important for me.
I don't remember fully open headphones from AKG since K1000, which are not exaclty conventional product by the way. AKG always preferred closed and semi-open constructions. That's why K5/6/701 are semi-open for example - they just excel in this kind of drivers.