Good news, folks.
I just saw there is Mi Home in Google Assistant Home Control setting page.
And the best part is it is MULTIPLE SERVERS SUPPORTED.
I don't know which server is supported but my XiaoMi wifi smart plug is in China Mainland server, Yeelight in Singapore server.
AND even if is multiple servers which my Mi Home can't be used to control my Yeelight , it is still appear on Google Assistant.
This means I can have Yeelight set in China Mainland and still can be found in Google Assistant through Mi Home action. I can link the sensor to Yeelight and at the same time voice control it using Google Home.
Let's give it a try and discuss here.