If you are video streaming, More ram is ALWAYS better. This Allows your game that you stream to be at the maximum settings without dipping into the stream ram.
2x8 GB minimum. 16 Gigs, then bump to 32gigs IF you decide to get into higher than 1080P
A 1070 8gb will handle streaming @1080P Silky smooth.
After that, You are getting an I7 7700k, Which is good.
FINALLY, Trust me when I say this. Get a 240-500gb SSD and run the games you are streaming on that; Your viewers don't like loading screens just as much as we do.