I haven't seen that article yet, but here's what I think:
Harry is definitely an Auror for the simple reason that he's wanted to be all along, and it's kind of obvious that JKR wants him to be, too. It's the simple answer, but it's logical.
Hermione, I'm not so sure. In DH, she says that she wants to do some good in the world. That means she'll probably work for some sort of non-profit organization, or possibly many non-profit organizations. As for Ron, I see him in the sort of small-time Ministry job that his father had, if not necessarily one dealing with Muggles.
As for Draco, I actually don't think he's going to have one. Did Lucius have a job, as such? I doubt it. Not that he hung around doing nothing all day, it's just that he had way more than enough money to take care of the family for several generations, centuries even, so he probably spent his time hanging around the upper echelons, putting his money where it would do him and his friends the most good, but without an actual employer. If the wizarding world has a stock market, he might have spent some time on that. But I can't see any of the Malfoys getting their hands dirty in the way a job implies.