Indeed. Some media are writing up that Waltz is Hannes Oberhauser, but that's certainly not information from EON or anyone else, so I'd advise real caution on that. As Harmsway says, the best information so far is from the Mail on Sunday report - so we should assume it's the newly created Franz Oberhauser, until further notice.
Given Waltz's age, it makes sense that he'd be Hannes Oberhauser's son rather than Hannes himself, given Hannes' role in Bond's childhood.
Is it possible that a certain cache of Nazi gold bankrolled Blofeld's early criminal activities? Additionally, is it possible that Bond begins by investigating Hannes Oberhauser's death, previously presumed to be an accident, and now revealed to be a murder, and *that* is what the "cryptic message from Bond's past" mentioned in the summary refers to?