Yes, this is correct .
1 battery - 1 hour to -1:20 of recording.
If your interview is 1 hour long then remember there is a recording limit of 30 min. per record.
Good discussion! I usually have both approaches: starting create edits, then looking for music and then selected music inspiring further edits or sometimes is even change all the video idea. :-)
My choice for music is http://tiny.cc/Royalty_Free_Music and latest video with using royalty free tracks is:
"Las Vegas - Night Strip Walk" http://www.youtube.com/watch?v=1Y4R3A0nrh0
(btw here I spent just $62 for all 4 tracks licensing which is very good as per my opinion)
Ronin M or equivalent gimbal mounted on the rope is another option.
Yes, you are correct, cropping 1080p part of 4K original will get you 2x focal length equivalent.
Personally I like this source of Royalty Free and reasonably priced music http://tiny.cc/Royalty_Free_Music
Absolutly different lenses to compare.
18-35 wide angle lens good if you need to shot close to the subject and cover a lot of background with everything in focus. This is lens if you plan to walk close to the cars.
70-200 telephoto lens good to shot from the distance with less background in the shot and less distortion. Also good if you need to have background not in focus but you need to be on distance.
I assume you have to check youtube videos for the lenses to see what type of image you can get from it.
Personally I have Canon 70-200 2.8 IS II and this is good lens, Image stabilization is good for videos. Not experienced with Sigma but I have Canon 16-35 IS with similar range.
Also it depens on camera you have. If it has crop senser then effective focal distance will be longer.
It might be good idea to get both lenses to cover most of the range for the flexibility.