Xiaomi sensors are likely to never be officially supported by either Hubitat or ST (or anyone besides Xiaomi)--they do use ZigBee, but a non-standard "profile," compared to the standard ZigBee Home Automation 1.2 profile that Hubitat, ST, and others support. It just happens to be similar enough that many of these can be tricked into pairing with and using the Xiaomi sensors anyway. I think the only reason people really like them is because they're cheap, not because they are easy to pair 
(though with known good repeaters, most find them to work well once you get past that).
Have you paired any to ST (sounds like you have)? If so, the process is similar but actually a bit easier since you can do it all from the Hubitat web/admin UI and don't have to split your time between the ST app and IDE like you do on ST. This thread has both the drivers and pairing instructions: [Release] Xiaomi device drivers
