... prompting my question on whether there is a minimum DH specified for the AS365. It has nothing to do with the prescribed CAT I minima of 200ft.
Ok, so now we know what we are talking about - as I mentioned, the N3s that I flew with a 3 axis AP could be flown down to 75' radalt on a coupled ILS but that was an aircraft capability not a regulatory permission to do so - I used to demonstrate it to my students VMC at the end of a normal CAT I ILS when we had been cleared to land.
I can't see how Airbus would put a limit in the RFM that was higher than they had equipped the aircraft for and the 4-axis AP with SAR modes can take you to the hover IMC.
I think it will just be regulatory permissions you require as long as you have a rad alt and twin ILS receivers.
The quote from the 169 RFM is a red herring - the limitation is all about the steepness of the approach due to the increase in RoD and its effects on stability and the pressure instruments accuracy - it may also factor in OEI go around capability. That is why it specifies a maximum glideslope angle which is not unusual but 4 degrees is quite a low limit - I'm sure you know that 3 degrees is the norm.