1) Yes, I consulted with a lawyer for the version in one language which became the basis for this project. Though this has just been the basis, as I said, and things have changed already, and are expected to change in the future. Some kind of regular review of the current version with legal experts may be a good idea. Apart from that, please see the disclaimer that is included for obvious reasons.
2) None. It's as simple as that, sorry! The important use case has so far been using the output to display on websites. But it's obvious that, having all the input available in a structured and machine-readable form, it would be a good idea to also offer outputs in various machine-readable forms and formats. The vision was exactly that something like a "privacy-policy.json" besides your "sitemap.xml" or "robots.txt" could be helpful and an interesting first step towards a larger "ecosystem", which must necessarily exist.
3) No. I just didn't have the time for that, yet. I also don't know if that's really something that lawyers could use or would want to use. But this is definitely an interesting idea that might be worth exploring.
4) The “Terms of Service“ are a completely different beast, I would say. There's probably not much that could be re-used, and the challenges have only minor overlap, although the concept is quite similar in general.
5) You would probably declare one policy to be your canonical version that really counts, and any translations would be for information purposes and assistance only, without legal validity. Turning to the implementation in this project, translations could probably differ somewhat from each other and wouldn't need to be exact 1:1 translations, word-by-word. Languages such as "en" could also be split up into "en-US", "en-GB", etc. -- not just for the purpose of handling small language differences better, but also for the purpose of adjusting this to the jurisdiction.