Right now, when we convert an existing talk page to Flow, we copy the wikitext above the first section into the Flow page's header.
We're doing this because we want to keep the metadata yellow boxes, but sometimes the wikitext above the first section is just a conversation that people didn't add a section header to. When this is copied onto the Flow page, it looks dumb.
So -- we should only copy templates onto the Flow page header. Anything else should be ignored, and just archived along with the rest of the page.