Could you provide some more information regarding #3, how much latency are you seeing on the automation?  I expect there would be a small latency between the DAW tempo value and the H9000s, because these automations are sent at a control rate not tied to the real-time processing rate of the DAW.

I’ve made two videos, but unfortunately MP4 is not allowed here… If you like I can send it via Email (would need then your address). But you can check this also very easily if you observe the TEMPO with and without Mixdown: The Tempo automation without Mixdown is gapless and smooth… (e.g. 100.1 => 100.2 => 100.3 => 100.4…..) As soon as you’ll make a mixdown, the Tempo will be sluggish and jumps at irregular intervals from 100.1 => 101.4 => 102.2 => 102.9….

(?)