Question about Hauck alpha tray

Yes, it fits. "Dining table for Alpha+ and Beta+ wooden high chairs" -
https://www.hauck.de/products...

No Idea, you may be better to check via the manufacturers website, they have a info@ for questions. I tried it on the Stokke Tripp Trapp and ofcourse it does not fit. So there appears to be some specifications. Good Luck!