2) There's been a couple of these, most recently Mammouth[0], but personally I don't think that's useful - the syntax is more or less OK. I do think that renaming the core functions and then providing an alias/compatibility library would be beneficial however.
Personally, the most inviting part of HHVM for me isn't the performance, it's the alternative team that seem willing to develop the language more in-line with what users want.
Totally agree with that. In the real world, one is normally using some sort of framework which hides most of the language quirks (inconsistent naming, order of parameters, etc). And the cases, when you need to use quirky native functions, are rear enough so that introducing additional layer where bugs might occur is not beneficial enough. So I'd focus more on picking the right framework (both philosophically and technically) rather than on focusing on a new language.
Why I mention frameworks that much? Because in the of majority cases, applications are just some CRUD with a bit of logic and going with flat php + some home made libraries is just waste of time.