Welcome to the wonderful world of webmentions James! Well, you’ve been here for quite some time already, collecting the webmentions. But it’s great to see you took the time to find a solution that works for you and is suited to your needs. It may not work for others, which is great. Because you share your code, others can build upon it and create their own solution. Which leads to a richer and more diverse ecosystem of solutions to get, send, show and share webmentions. It might get messy, but that’s life.
Off the top of my head, I’d probably filter out all “likes” and “bookmarks” if I had those issues and only display comments.
You might consider showing likes and bookmarks in a different manner, with facepiles or other creative ways. But then again, it’s all up to you!