I think however, that they removed hyper threading from the 9th generation i7 CPUs. So to get that, you'd need either to go with the 8700 or a new i9.
You mention wanting to stream as well. Have you considered an AMD ryzen setup? Something like the 2700x? The Intel CPUs will be slightly ahead in gaming, but the 2700 or 2700x are both 8 core, 16 thread parts. For streaming, either of those should be great.
Found a Reddit discussion on this very topic which may help you as well.
View: https://www.google.com/amp/s/amp.reddit.com/r/Twitch/comments/8ghqy3/need_to_upgrade_my_cpu_ryzen_2700x_or_i78700k_for/#ampf=undefined
I also would mention that another reason to go with the AMD setup is that Intel tends to change sockets every other year or so. So when you want an upgrade, you are buying a whole new motherboard/cpu etc. Whereas AMD has stated they will support socket am4 into 2020. So you could start with the system now, then in a year or 2, if you decide you need more power, you might be able to just do a bios update, then drop in a ryzen 3000 or 4000 series CPU (which I might add, leaks for the 3000 series look promising).