Not sure how I missed this. Some useful stuff for indieweb in WordPress. More links and rabbit holes in the comments too. Bookmarked for the summer holidays.
Although the appropriate microformats are usually built into the Webmentions plugin. The plugin for theaded comments can be a bit more tempremental. Chris Aldrich recommends manually adding the reply class and URL just to make sure:
<a class="u-in-reply-to" href="http://www.example.com"></a>
I have come to do this out of habit for replies now.
Among other interesting snippets.