A tested and working state of manual post import is available:
You can deactivate/delete your existing Patreon WordPress and upload/activate the above package.
At the ‘Star a post import’ section of Patreon Settings, you can now manually import posts. When you start a post import, the section will transform into an ‘Ongoing post import’ state, allowing you to import the next batch of posts by clicking ‘Import next batch’ button which will appear. You can do this every 10 seconds.
The status messages will guide you through the import.