This looks pretty good, and I like that it's fairly lightweight compares to some other options.

My suggestions are mostly along the same lines (and having not seen the source code) - use a plug-in architecture for some things. MySQL is fine, but a lot of companies use PostgreSQL. Google OAuth is fine, but many companies like Auth0. You main project provides a stable API for each option, but the end-developer can swap out PGSQL for MySQL if they choose without needing to change any code (well, maybe their SQL).

Your FAQ mentions some templates (HTML I assume?) but that's not shown in your Features list anywhere - devs will want to know what pages have already been stubbed out for them.

Good luck with this!