I don't know, these are the thoughts:

a) I don't know the minimum version requirement of pdf2htmlEX that we need. I have 0.9 locally, homebrew's latest version is 0.8.1. I would look to @sathomas and @simong to clarify that
b) There were some recent bugs that were fixed for Stephen in pdf2htmlEX by the maintainer, so I think we would need those which probably implies we still need latest master as in these instructions, but perhaps Stephen knows more because he's removing the instructions to install from master?