All this nonsense about re-recording the voice lines is ridiculous. They HAVE to re-record the voice lines, as the original voice actors contracts only cover the original FO:NV, not some FO4 mod.
On the OTHER hand, I'm betting that one of the first 'mods' for this will be re-inserting the original voices. It'll be super simple, probably just moving the files from one directory to another, and re-naming them at worst.