Will the new Studio Display charge a 16" MacBookPro?

Yes, it will.

But not FAST-charge. It can fast-charge a 14-in MacBook Pro.

I see no indication that it can be powered from your device. It seems to want to Power your devices from ITS power supply over ThunderBolt or USB-C.

The specs say it requires AC power 110 to 240 Volts, 50 to 60 Hz. The picture on the stand shows an AC power cord poking through a hole in the stand, with a round black blob at the device body, black in color.

I think not showing a cord ships in box is an error of omission.

The Studio Display ships with an "Attached Power Cord" thus the picture with cord shown poking through hole in stand. "An error of omission," Apple does not make mistakes of this nature (heads would roll). Since the cord is permanently attached, it is a part of the monitor, and not a separate item in the box.

On paper it should be able to charge the Mac Book Pro, but the Studio Display does not ship with a power cord, so you would need to supply a power cord.

(I base this on the "What's In The Box" section when you order the Studio Display.)

<< the Studio Display does not ship with a power cord >>

Honestly, how can it NOT have power cord. There is no use-case a where a power cord is not required.

It could be powered from a Mac Studio via Thunderbolt.

I guess we'll know for sure when it ships. My hope is that you are correct and I am wrong on this.