Will the 4x4 Mimo work if we use Mikrotik LHG-HP5 with an elevate, or must the station be cambium?
No. You need an AC Cambium CPE to take advantage of MU-MIMO.
Are you asking if MU-MIMO will work ? If so that only works with ePMP AC client radios (it doesn’t even work with ePMP N clients much less elevated N clients).
Assuming LGH-HP5 is supported maybe you are wanting to know if it will benefit from 4x4 in the form of more gain/rssi ? I don’t know the answer to that one, I can’t even see that our ePMP N radios gain anything on the 3000AP over the 2000AP.
I wouldn’t mind knowing the answer to that last one myself. As we really don’t have a ton of use for MU the only real advantage for us is hopefully getting more RSSI from the 4x4 but I only have 2 3k APs in use right now and I really haven’t had time to do any real testing.