For rendering and video editing, you will basically want
1. every extra cores you can get.
2. as big as RAM you can get
3. as fast as storage you can get, m.2 SSD is the best, if your mobo supports it.
4. if your software can use CUDA cores or OpenGL, get also the best out of this.
You plan to have:
- GTX1070, this should be already enough. Forget GTX1080, go to GTX1080Ti, if you want something stronger...psst!..you can game on it as bonus...
- 16GB RAM. Can you still bump up to 32GB?
- Ryzen 7 is a minimum. Go to Threadripper if you can still afford it. (I am also still planning/considering to upgrade my E3-1231V3 to any of these Ryzen 7 or Threadrippers)
- Get a mobo with m.2 support and get a really fast SSD with this interface.