Amazon preorders are now available. I'm not sure why they included screenshots of Genso Wanderer though.
Only tangentially related, but there was a stream for premium members of Nicovideo after the regular stream where they interviewed ZUN. Someone was nice enough to make a rough transcript, so I'll put some of the more interesting ones here:
Q. Do you have slumps and how do you get out of them?
A. I do, but I don't have any method other than drinking my way out.
Q. How long do you devote to your creative activities in a day?
A. About 8 hours, lately. It used to be more.
Q. Any recommendations for sightseeing in Nagano?
A. Hakuba
Q. What's your favorite proverb?
A. "Curses return upon the heads of those that curse." (but the Japanese version which is basically "Curses have two holes.")
Q. Why have the characters' clothes after defeating them not been as damaged as they had been?
A. Because the average age of people playing the games has gone down.
Q. What do you see as a good goal for making your own game?
A. Try to make it in less than a year.
Q. Do you have plans to add voices to your games?
A. Well, it's not that I don't want to...
Q. Do you have a PS4?
A. Yes
Q. Why did you call the games "Touhou"?
A. Ask the college me.
Q. Has having a child affected your works?
A. In the sense that my life in general affects my works.
Q. Why did you release Line Stickers?
A. Because someone made a set of imitation characters, so I did it to prevent it from getting worse.
Q. Any plans to release a game on PS4?
A. There was, but the PS4 didn't exist then.
Q. How can I make my fan works canon?
A. Bring them to the publisher! (No guarantees.)
Q. How long does it take for you to make a song? And what's your favorite?
A. Anywhere from 1-2 hours to a whole day. And while my favorites change a lot, I've liked Omiwa Legend for a while.
Q. Have you been to places related to your games?
A. I've been to some, but not others. And of course, I haven't been to the moon.