How to convert HDV to dvd full resolution 640 x 480?
Whenever you publish something to end-users you ALWAYS want square pixels, everything else WILL make problems.

So just convert your anamorphic video to a square pixel aspect ratio. Handbrake should automatically handle that, the settings you have right now should output a video with square pixel aspect ratio. Just add the vertical resolution.

Is there any reason why you would want to crop your video to 4:3? A down-scaled 16:9 square pixel resolution would equal to 640x360 for a "SD" resolution (bare in mind there are several different DVD standards) and I would suggest you to use that resolution and don't just crop your video unless you have an artistic reason for that.

If handbrake is unable to handle the non-square pixels you will have to reside to use either a full fledged video editor or alternatively FFmpeg.