Is it possible to mix DSLR videos with DV videos in an editing software?

I'm a video editor & photographer. I'm planning to buy Nikon D800.It will be used both for photo shoot and video shoot. Also one of my friends shoots video in a HDV camera (Sony HVR Z5). He shoots in DV mode. Now my question is can I mix both DV video and DSLR video together for editing. I use AVID STUDIO and ADOBE PREMIERE PRO CS5 for editing.
If it is possible, then what should be the setting in both the cameras & editing software?

Yes, it is possible. Default settings in the cameras and software should be fine. It may be easier to get the video into a common format - that is, import them as different projects, then export one and drag exported file into the *main* project with the other (directly) imported video. This is not much different then bringing stills into the video (though the stills can be pretty much any format, jpegs are fine).

Tip: white balance on the same card at the same time.

Your editors can use either DV or HDV in the native mode. It is unlikely that they can use video from the D800 without converting it first. The codec in the Nikon is the worst of the three for editing, so you will want the editor to work in either DV or HDV. If your end product will be a movie DVD, then you should convert and edit in DV mode exclusively.

I recommend AVS Video Editor. Very easy to use, simple and fast enough for casual use.