I know this is probably a very noob question...

Can one project have someone working with Windows Esenthel, and another person working with Mac Esenthel? Are they interchangeable in the same project? Or does everyone have to use Windows or everyone use Mac?

I create files using Esenthel on my mac, and they compile file on my PC without modification. So I'd guess that they're interchangeable.

yes they can work no problem, however Mac SDK is not released as often as Windows SDK, so sometimes you may have some codes (EE C++ functions) from latest Windows SDK that isn't yet available on Mac SDK, and project won't compile.

ok thanks for the info