Yes contributors have direct push capabilities. They can also merge PRs. (edit: I think they’re actually called collaborators.)
My suggestion would be the only people that really need contributor status are the curators of the codex, and that all contributions should generally go via a PR. This gives the curators the opportunity to ask for format changes or via the magic of git cherry-pick (or interactive rebase) make the changes on behalf of someone else while maintaining authorship (e.g. this commit to Teletype). It also makes it easier/safer for new users to git, as you can easily get in a muddle with direct repo access.
GitHub tracks code contributors and code ownership independently of who has contributor status on the repo, e.g. see the listing for the Teletype repo (go me!). That’s the best way to show people recognition.
Also, if you’re willing to put the time in, it’s better to go with the benevolent dictator for life model. Or at least a core group of dictators. Time and effort are the limited resources, not opinions. I’ve seen open projects sidetracked due to too many opinions. So if you have a plan go for it, you have my vote for BDFL.
One last thing, hopefully Hacktoberfest will happen again this year. In short anyone that opens up 4 PRs on GitHub in October gets a free T-shirt from GitHub (where we store our code) and Digital Ocean (where lines is hosted). It might be a fun way to drum up interest in contributions to the various Monome open projects (this, the Teletype docs, etc).