I think you're really trying too hard here, ZeroBlue. If you want to believe it, then go ahead, but I find it silly to think that a pegasus could do a hadoken. I don't find the conversation interesting anymore, but I'll finish my thoughts on it from what you see as vindication (when I'd have trouble even calling it "evidence.")
Zecora's been doing magic for a while now. That is nothing new. But all of which involve mixtures. She's never glowing or anything, and she doesn't appear to be concentrating or focusing while performing that act. It's not her own ability to perform magic so much as it is her knowledge of magic.
(Or to take a phrase and use it here, science is indistinguishable from magic without understanding.)
It's never explained why she could refill her cup from nothing, but that doesn't make it magic (and it most certainly doesn't mean it's a manipulation of energy.)
- Water is not energy. There is a large difference in conjuring water and concentrating energy into a blast. So even if Dash could learn the properties of what mixture Zecora used, it still would be far removed from any ki blast.
- Energy used to refill water without moving it from another source indicates magic of a different nature. It's probably not raw ki so much as it is a spell or incantation.
- Or it could be a magicked cup. Think of a cup with a spell that can somehow duplicate the remnants of the cup by running your hoof around the edge. Always check to see if there are alternative hypotheses. That's part of the scientific method.
Besides, Rainbow Dash is probably the second least likely of the six to train with the discipline of a monk (far ahead of Pinkie Pie). Dash might sprint and fly about to train, but she's not going to sit and concentrate for hours learning how to temper any "ki" a pegasus has (assuming ponies have "ki." Remember, this is a universe of talking ponies where the sun is regularly raised by an alicorn, and a shadow sombrero nearly took over the land by grunts and torturous nightmare doors.) One can't assume the same sort of mechanics in regards to energy and magic as our human theories in fantasy do.
I mean, if you want it for a fanfiction, then go for it. But it's far from canon.
- Or it could be a magicked cup. Think of a cup with a spell that can somehow duplicate the remnants of the cup by running your hoof around the edge. Always check to see if there are alternative hypotheses. That's part of the scientific method.
EDIT: I love you Pyro.