80D is a good camera. Here is the review that I had done earlier: https://www.indiawilds.com/diary/canon-eos-80d-review/

The difference between the reach of the 70-200 f4 lens and then 150-600 is a lot. If you would have asked to select between Canon 100-400 IS and Sigma 150-600 then I would have prefered the Canon 100-400 due to the quality and because the Sigma is slower and you can slap an extender to get similar length if it is really required. However, since you have asked for 70-200 and 150-600, the difference in reach is way too much. If these are the only two lenses you would like to compare, then go with the 150-600.

Video needs lot of learning. That may not be evident when people say that one can effortlessly shoot Video in DSLRs. So be prepared. It is not just about Sigma. It is the way video is done in DSLRs vis-a-vis dedicated video cameras.