could i use nonstatic members inside a static method?
eg.
$this->nonStaticProperty
$this->nonStaticMethod()
and vice versa that is to say use static members inside non-static methods?
From http://php.net/manual/en/language.oop5.static.php
Declaring class properties or methods as static makes them accessible without needing an instantiation of the class. A property declared as static can not be accessed with an instantiated class object (though a static method can).
You can't use non-static members in a static function, since they're outside the function's scope. But you can use static members in a non-static function.
Not really, as you can't use $this in a static context.
As a static member doesn't have an instance, it can't call instance methods (unless you create an instance inside that method).