Day dream is the feature for AmoLED display Smartphones...
Daydream consumes more battery making your Mi Smartphone's battery life short.
If you still wanna try the feature then you can with some 3rd party applications available in the Play Store.
i have redmi note4 . . 64gb version wd nougat miui 8.5.4 stable version
Currently Split Screen is not supported on your MIUI version.
Developers are on it to get it up soon. We're sorry for the delay but, Split Screen is available on MIUI 9 Global Beta ROM.
I hope you understand.
We appreciate your patience.