I realize this is an old question, but it made me curious since @peepeep pointed here from another topic. I changed the name of a Wyze Bulb Color by adding emoji to the name in the Wyze app and then looked at the bulb’s settings in Google Home, which reflected the change in the “Name from Wyze Home” field. When I asked my smart speaker to turn on the bulb for a minute, it responded by telling me that it would do so but used the non-emoji name I had previously assigned it in Google Home, so I think that answers your question.
In order to get Google Assistant to respond with what it was going to do with the voice command, I had to move the bulb into a different virtual room for the test and then specifically ask it to turn on that room for one minute. Interestingly, if I try renaming that room by adding emoji, then Google Home warns me: “May not work with voice commands.” This didn’t happen when I tried adding emoji to the device name in google home.
Tangentially related name quirk
I’ve also learned through previous experience/experimentation that Google Home/Assistant voice commands can use at least three different names to refer to a single device, depending on how it’s configured. Google Home knows the device’s room, the device’s name it’s assigned in Google Home, and the device’s name it brings over from the third-party app where it was initially configured. If I have a single smart bulb in a room, for instance, I can ask Assistant to control it using any of those three names.