Just talked to the Samsung USA rep for T-Mobile today. Take this with a grain of salt but he says:
US will get SD 835, 8GB RAM, USB-C, 2K resolution screen, two edge style S8's (no more flat screen model), home button is gone and fingerprint reader area will be at the bottom portion of the screen (just above the bottom bezel) and that recent image leaks are pretty accurate.
P.S. And pre-orders will start end of March and the S8 WILL BE in T-Mobile stores on April 18. (According to him. We shall see.)
It's highly rumored that Samsung will have the 8 GB LPDDR4X memory chip from SK Hynix.
http://www.anandtech.com/show/11021/sk-hynix-announces-8-gb-lpddr4x4266-dram-packages
With the display, It's also highly rumored to remain 2K(QHD), But they will ditch Diamond Pentile for RGB, which will increase sharpness and quality, since there will now be 3 subpixels to a pixel instead of 2.