I am not able to reproduce your errors. The most recent releases of device driver code for the Mi Cube and Xiaomi Honeywell Smoke Sensor can be saved without error as Hubitat hub device drivers on my Hubitat Hub which is running the most recent hub firmware as of today.
My guess is the same as @bertabcd1234:
The SmartThings hub does not have the PushableButton capability, which is why I guess that you may be trying to save Hubitat device drivers as Device Handlers on a SmartThings hub.
Just received the Aqara xiaomi smart lightswitch QBKG03LM this light switch has two buttons and relays needs no neutral to switch and drectly replaces a UK light switch. The Hubitat hub sees it but, as know surprise, as a device. Time to play.
I'm just starting to migrate some devices from my smartthings hub to hubitat. I added the driver code for veeceeoh's Xiaomi Original Motion Sensor from this thread, and removed one of my xiaomi motion sensors from smartthings (removed device, held reset button on xiaomi til it flashed 3 times). I went to hubitat and started discover devices, and it showed up, but appears to be stuck on "initializing...". This is the first device I'm pairing natively to the hubitat (did hue already, but that's a LAN connection), and I'm not sure what's supposed to happen after that.
I remember having to manually set up the device in smartthings, with a piece of the uuid from the discovery, do I need to do the same in hubitat?
That's not a possible solution here, nor is it needed. Remove the battery for 30 seconds, then try pairing again. Xiaomi are sometimes a pain to pair and will get stuck at initializing. Just try again. Once paired they work well as long as you don't get too far from the hub. You'll need either a Sylvania Smart+ plug (not version A) or a Xbee if your Xiaomi devices are more that roughly 30 linear feet from the hub.
I had to hold the reset until the LED flashed three times .... the initialization usually starts then. Then I had to push the reset (and release) button about every two to three seconds to keep the initialization alive until the device completed discovery. Sometimes it took another 30 seconds to complete the discovery process.
I usually hold for 10 seconds, which is probably the time is takes for the LED to flash three times as @Matthew says he does. I've had mixed results with the tapping every 2 or 3 seconds, but I still do it. 
This is a long thread, but you'll find some good suggestions here (and a bit of a detour onto Xbee for a while) that should help. As you probably know, they're not using standard Zigbee protocol and so they can be a pain to get paired. One paired, you just need to keep their signal strong and they'll continue to work like champs. Very happy with all my Xiaomi devices on Hubitat.
What exactly does the Lux Value Offset do? Will it make it more sensitive?
Never used it myself but I'm assuming if you have a very accurate device to measure lux, you can then put an offset in to give a identical reading.
Lux measuring device = 100.
Aqara device = 110.
Put in - 10 as an offset and it now reads 100.
Only guessing here and I don't know what will happen when lux reaches 0.
It makes more sense for temperature or humidity readings. Not sure it's really necessary for lux reading.
It does not change the sensor's sensitivity, but rather adds the user-entered offset to the value reported by the sensor. @bobbles's explanation is correct.
Ok thanks for explaining for that!
Thanks @veeceeoh, step 9 allowed me to add a couple of different types of Xiaomi devices that wouldn't finish Initializing.
I have added few Xiaomi devices/sensors and most of them have worked fine. However, I do not know how will I use the cube and LIght switch. Could someone provide some instructions.
Any DH out there for the xiaomi wall plug?
@Smartsmartsmart reported over here that the SmartThings DTH code worked for him (but without the energy usage capability).
I am currently working on a SmartThings DTH for the new Xiaomi Aqara Vibration Sensor (which will in turn lead to one for Hubitat), but after that I'll see about adapting the SmartThings ZigBee outlet DTH to make a Hubitat-specific device driver. I just won't be able to test it myself.
I knew eventually you would get to it. I just got 4 of them this week. Let me know when your ready to test. I made my own driver (based off the smartthings driver) but prefer to you use what you guys come out with as its a "supported" driver.
You mean the beta DTH in the bspranger/Xiaomi thread? That would also be me, with help and input from a few ST users, and notably with help and some fantastically useful code from user oltman on GitHub.
As for the adapted Hubitat device drivers, "you guys" = just me. 
Sweet, thanks for that got it working like a charm!
That's me here.
I just tested it again and it worked, however, if I press the button on the outlet, it doesn't do anything.
Could you please tell me how you got it working? Which driver did you use?
I tried to use the ST driver but I am getting an error message while saving.
That would be great. I own one and it would be nice to have it working with Hubitat.
I will do the testing for you. Let me know when you are ready. 
Download the Hubitat app
