Fredngeorge: So far, they're a single character

I'm starting my review of the seven novels to see how J.K. has depicted Fred and George Weasley: as two different individuals or as a single character with two names?

With the review of The Philosopher's Stone almost completed, here are my initial thoughts on the subject: as she wrote the first novel, Rowling didn't plan to portray these guys as two distinct characters.

Their first introduction comes in King's Cross Station as Harry searches desperately for a way to reach Platform 9 3/4. He spots this family of redheads with an owl (!!!) on their trunk and thinks, "Aha! They must be heading to Hogwarts train too. I'll follow them."

Two things jump out at me from this scene.

First, Molly Weasley actually asks her kids what Platform the train is on. Isn't that bizarre? Throughout the rest of the novels, the fact that the Hogwarts Express leaves Platform 9 3/4 at 11 a.m. on September 1 is one of those great accepted constants in the world. Everybody knows it. Everybody banks on it. Furthermore, Molly Weasley has probably been delivering kids to the train on Platform 9 3/4 every year for the past decade or more. And yet she has to ask her kids in this first book which platform. Wow.

Second, the first thing we learn about Fred and George is that everyone, even their own mother, can't tell them apart. Throughout this scene and the following scenes on the train, we learn their names but we get no indication from the author of any difference between them.

As the book progresses, J.K. even goes so far as to skip identifying which of the twins delivers which line of dialogue. She presents conversations involving Fred and George as if they are a single person: when Harry, for example, talks to the twins, the twins' side of the conversation is never attributed to either George or Fred.

Weird. Neat. But does it change?

My expectation is that I will, indeed, find differences between Fred and George written into the later books. But I may find them indistinguishable until we get to The Goblet of Fire at least.