Do you have ImpulZ LUTs for the BMPCC4k/6k?
The ImpulZ LUTs for BMDFilm are based on the color model, not the device specific sensors, so yes - both of these cameras are supported when the footage is interpreted as BMDFilm. There are however a number of different flavours of BMDFilm to keep in mind. I'll get to that in the next question.
Can the Ursa Mini Pro LUTs be used on the original URSA Mini 4.6k?
TLDR: Yes - as long as you adjust the contrast manually.
There are different versions of the BMDFilm color model for different camera types which is why we included the Ursa Mini Pro LUTs as a convenience. These different versions really only affect the gamma curve so you can use the LUTs pretty much interchangeably. It's safe to apply Ursa Mini Pro LUTs to non Ursa Mini footage and then dial in your own contrast curve because the primaries of the BMDFilm color model are shared by most Blackmagic devices.