Yes, LG has already announced that Android P update is already in development.
Yes, LG has added voice recognition in LG G7 Plus. This is actually a combination of a new chipset, a few mics and Google's AI. The G7 Plus can recognize your voice from up to 5 meters distance even in a noisy of surrounding and can launch Google Assitant in an instant.
LG G7 Plus has 8MP resolution front camera and its aperture is f/1.9.
Yes, LG G7 Plus does support face unlock.
Yes, LG G7 Plus does have the NFC support.
The LG G7 ThinQ comes with some very appealing features that include a Super Bright Display, a dedicated Google Assistant button, DTS:X surround and an incredibly loud speaker. It also comes with a notch which may not appeal to everyone but its powerful specifications and strong feature set make it a worthy contender.