The drivers/smartapp are already ported to Hubitat.
I was under the impression the Mi hub has both control methods local & cloud. so I blocked the internet from the Mi hub and I can still control the hub(change light & sound) via being on the same wifi and using mihome app. I did not get any logs from the door sensor while the internet was off, but I know the hub is still getting the zigbee signal from door sensor, so possibly once the connector is setup, we wouldn't need internet for miHub? but Keith would know better than me.
I have an RPi and have everything setup, the hubitat smart app is finding all 3 devices plus the lumi hub, but none are showing as devices in hubitat, even with drivers loaded. I'm having fun but I've invested over 15 hours fiddling with this. The documentation is sparse and if I can ever get it all functioning properly, I will do a video, as I had to piece stuff together from 5 different posts on various forums.
If the Mihub has to have internet for this to all work, well then, guess my xiaomi devices will stay on hubitat.
Although I'm kinda pissed off, my xiaomi were more stable on ST. I heard some rumblings about an issue with zigbee stack on Hubitat, that supposedly is being worked on, but apparently it's a big job...