1. Everything you seem to be asking for seems like it is not relevant at this point in the project's lifecycle. 2. IMO people who are capable of providing good contributions don't actually need what you are asking for. They can review the README as is, review the source code, etc.
In short, patience.
It would be interesting to see examples of specific such advantages that could be gained, because I'm having a hard time thinking of any.
Two days later I got a one-star review on the now-defunct cpanratings site complaining about the lack of documentation.
Personally, HN would be my go-to if I had a project to show and for which I was hoping for some high-quality collaboration.
If by 'reaching directly out' you mean contacting specific people, then it shouldn't be a public repo. Like I said, it's under a Facebook org, of course others will find it.