The fact that likes count and half the replies are missing is not specific to AP but to implementations not willing to actually follow the AP community: in fact the SocialHub (https://socialhub.activitypub.rocks/) community is the place where all coordinated development happens, and solutions to those issues have already been designed and implemented in multiple softwares, with the notable exception of Mastodon. Maybe that's the issue: people keep looking at Mastodon to understand AP, but Mastodon is one of the worst examples of AP, even when talking only about the technical domain. It doesn't implement the C2S API, it doesn't have portability, likes counts and missing replies as you said, ...