I will be very impressed if everything turns out to be a hoax, given the volume and quality of some of the early screenshots (like the elephant). Most of the guide pages, ultra blurry ones notwithstanding, do look pretty convincing. But in general I agree that there's going to be a lot of fake stuff thrown in during lulls between anything legitimate that may be leaking, and that Cinderace image is a top candidate for something suspicious. It did come out at a notable delay after the Intelleon & Rillaboom image, definitely enough time for someone to fake it and match the style, so if it turns out to be fake it wouldn't necessarily invalidate everything, but it would cast some much-needed doubt on things.
Similarly, with regards to the possibility of datamines, I'm not going to believe anything about impending datamines unless I see SciresM, Kazowar, or Kaphotics saying they are imminent.
I would consider any image with that quality and background fake. The kitsunoh "leak" and several others that have followed have all been this same blurry grainy format with that same background. Rillaboom and the snakes had similar backgrounds but much clearer image quality.