EK operates by the GCAA, GCAA takes most of its regulations from a hybrid FAA/EASA mix.
EK do allow pax to use phones after landing correct, they will also be looking to introduce the same regs as the FAA now for PED's.
On EK it is required that all window blinds be open for take off and landing with cabin lights dimmed/off for hours of darkness.
The reason for the window blinds being open is so that you can see outside. For example if an evacuation is required the cabin crew can see clearly outside the window from the inside. As we all know its hard to look out a window when its bright inside and dark out.

With regards to sleeper service - as of yet there are no plans to introduce it. Yes you are correct, cabin crew have to go through the whole "welcome to emirates, skywards, languages bla bla bla" because they can face a disciplinary if there is an audit manager or mystery shopper on board.
The lights is how it is, they switch them off as soon as the service is completed.
There are "service routines" for different sectors and different times of departures but no thing like sleeper service akin BA something I know very well.
EK will not do this though because they'll think that they are making it easier for cabin crew and thats something they think is a cardinal sin.