Sorry, I almost forgot that I still owe you an answer on this.
I think Hauf is a bit underrated, because there is not that much flash to his game and his skating could hold him back. But most of the times I have seen him, I saw a player with a high hockey IQ making smart plays especially in the offensive zone and also in transition from defense to offense. He knows where he needs to be on the ice (but he needs to improve his skating to make sure he can get there at the higher levels).
I also like his vision and his passing. They are not necessarily highlight reel cross ice feeds or no look passes, but smart, simple and useful passes creating chances for his teammates. I like his stick/puck-handling and his poise with the puck (will be interesting to see if he can maintain that at higher levels).
His shot is decent, neither a strength or a weakness right now.
His defensive play is suspect at times. Improved skating and coaching should be able to help him there. From interviews he also seems to be very aware of the areas he needs to improve and he appears like a coachable guy.
I don't think he will ever be a line driver at the highest levels, but he could become a very good complimentary player at the DEL level and even for the national team, if he pans out. And so far he has adapted well to every level he has played at.
There is of course a decent chance that he tops out as a DEL / DEL2 tweener, but I like these players with good hockey IQ as a basis, because that is hard to teach later on and Hauf has that in my eyes. As of now I expect only Lutz to be drafted and I think Hauf will end up as good DEL player who may get a chance to play for national team occasionally, though not on a regular basis.
It will be really interesting to see if he can adapt to the WHL and succeed there, when so many of his countrymen have failed to establish themselves there in recent years. And when I say succeed, I don't mean like Draisaitl, I mean like Eisenschmid who did well enough and eventually came back much improved.
Anyway, these are my thoughts. Feel free to disagree, I am more often wrong than right after all.
Cheers.