Yes, to register a class method (not static) as global function, you will use asMETHOD. In order for it to work the object pointer must also be informed at registration.
Object obj; engine->RegisterGlobalFunction("void func()", asMETHOD(Object, Func), asCALL_THISCALL_ASGLOBAL, &obj);
It is. It would appear that smaller independent developers that manages to get success are much more likely to support open source projects, than the larger developers that have more regular successes. My guess is that it is because these smaller developers are much more likely to know how it is to be short of funds, and thus more likely to sympathize with other small independent developers.