Help calculating proper Depth of Field?

You want a depth of field of about 1 ft to cover a head add in another foot to cover some movement. A upper body shot on the D7000 with a 50mm lens, landscape format, is 6 to 7 feet.

Your calculator is fine, but you may want to adjust the circle of confusion to 0.04mm. The video format is lower resolution than a still so you can use a larger CoC.

Based on a 50mm lens, distance of 6.5 ft, CoC or 0.04mm you could use a f-stop of f/5.6 and get about 2 ft of depth of field. Wether this is shallow enough to blur the background is going to depend on how far back the background is. This should give you a starting point. Set up do some filming, see if things look right, if not adjust the aperture a bit in either direction until they do.

The 35mm lens will let you set the camera up closer, so you may be able to have the head closer to the camera and the background farther back. This may help the look. Just remember the background will have to be bigger due to the wider field of view.