Ana explained it better, actually, so here: "Personally, the idea of it being played out as an IC creepy Kiseki thing sounds good. (...) Maybe people could remember Subaru himself vaguely (like MR and CH's dinner thing, they could be like "Wasn't there someone that we invited over...?" Or Kamui feel like "There was someone I talked to yesterday...", that kind of thing.) But definitely not remembering the things he said."
This will apply to things like Mokona's and Eriol's posts, etc. I'm really sorry for all the trouble, but hopefully it all makes sense. As always, please ask any questions you might have.