I know that emojis have been an issue in the past, however I manually remove it from the slug these days (see url
https://collect.readwriterespond.com/indigenous-for-desktop/). The only emojis are in the title?
I think that you have touched upon my only concern/frustration with Micropub/sub Readers. They do not seem to populate Response Proporties box. Although it is far from ideal, I prefer to populate these and even add my own custom quote. I also lose control over the headings associated with responses, listens, likes etc … I agree to this as a standard, but there is a part of me that likes having a heading and an emoji to go with this. Each to there own I guess. My dream would be to be able to decide what fields are available, like a custom client that matches up with the various microformats.