I think I’ve successfully introduced the concept of asynchronous Webmentions to my site and Lighthouse. It does look like that’s the only kind Lighthouse might be able to accept. It relies on the sender providing a callback URL that’s sent a post of the same target and source whenever it notices a change. Usually, this shouldn’t be often but I do it to allow for slower services or passive retries.
That said, Lighthouse is successfully handling this and I think I’ll begin working on the extraction of a feed to place into a reader soon. That and having a facility to render Webmentions on one’s site will be key! Lighthouse does have a hard requirement that people leverage IndieAuth and that’s largely to reduce the number of domains / sites that one can have monitored. But I’ll have to eventually refactor that because I do want to have a per-site experience for myself (giving each of my projects their own site will be better for me to separate into my reader).