Joshua is likely an internet sensation for physics videos that he's posted on Youtube (think Charlie McDonnell's Fun Science or the Vlogbrothers' Crash Course stuff). He would totally not realize it until his sister checked his comments/views and asked him when the hell he became an internet celebrity.

Helena... I have no clue. I strongly suspect it has something to do with someone finding out that HG Wells was actually a woman, and Helena writing about it.