In the functional example, where does Person store the fName and lName variables? Is there an intrinsic/hidden 'this' pointer? If functions persist data, are they really classified as functions anymore?
The message passing part isn't very relevant, as the concept of calling a function pointer via string lookup is present in many dynamic languages (Ruby, etc).
They are called closures. They are "environments" in which variables live, each of which can have a parent environment dictated by whatever rules there are. (Some programming languages have it where every use of curly braces creates a sub-environment; in JavaScript originally only the function keyword would introduce a sub-environment and if you write `if (something) { var x = 123; }` then `x` belongs to the parent closure and it might contain `undefined` if the branch was not triggered. Since then JS has introduced let/const which are scoped to curly brackets.)
When you declare a function it still has access to the full space of variables which it was lexically defined with. If you mutate those with one function then another function which has access to that environment can see those changes, etc.
There is no intrinsic "this", the code as presented is using a closure. Closures are typically considered a standard part of functional programming.
With a closure? And you get state hiding too.
> If functions persist data, are they really classified as functions anymore?
Sure, since otherwise returning a function from a function wouldn't be very interesting.