tnr’s content isn’t free; so a bugmenot username shouldn’t enable access to subscription content.

Yes – if it’s “subscribers only” then I would say there’s a halachic problem with posting an entire article, even if you get your hands on it. Reformatting to pdf wouldn’t change this.
Maybe just quote relevant passages?

But the bugmenot user name does work. that’s kind of the idea, that one person lays down the money and everyone gets to share the knowledge. you can address hte halachic issues for yourself.