No. Nokia 7 Plus does not support face unlock as of now. It is expected that Nokia will soon release an OTA update for it.
Yes, Nokia 7 Plus does have the OTG support.
No. Nokia 7 Plus does not have the notification light. But it does have the ambient display, so you will always get alert on the display.
Yes, you can record 4K videos with Nokia 7 Plus at 30fps.
Great battery life, immersive display, solid design, and software at its purest, that's the Nokia 7 Plus for you.