So is it 30fps or 29.97? The DV files I presume will run at 29.97 so as long as your offline/ online workflow doesn’t change frame rates it should work.
That said, Media Managing the final edit to Compressor converted ProRes would be better than relinking the mp4 files. Making the mp4’s to ProRes will mean no render and should be at least as fast as rendering the mp4s in a timeline. It also means that the ProRes files, like the DV can be 29.97 in case the flip files are not.
Also make sure the DV files audio is 48khz as the audio from the offline will be your master audio for mixing. Again this is why matching frame rates in critical. If you send the audio to an external system to mix then 29.97 will be expected. You may have sync issues otherwise.