PiP only works on YouTube Red.
WiFi speed will only show up on open networks and not secured networks as shown in your image.
Ok, what about this?
Google said it is a phased roll out, it isn't going to appear on every device the instant you get 8.1, i would imagine Pixel and Nexus devices get first dibs.
1. Clock icon works only in the native launcher. I have MS Arrow launcher and it doesn't work in that.
2. Google said only for Open WIFI networks, speed will be determined. Not sure how Google can know the speed if its a private encrypted network.
3. PIP works only in the Youtube APP, nowhere else.
4. Different clocks. Yes, it will show if you have setup different timezones.