Oh my gosh... this is just SO adorable!! Haha probably better than my Pony Christmas picture, I gave Mando and Wild Fire coal... actually no, technically Wild Fire didn't get coal - she got something much, much worse! xD ...and for that, I got coal... Oh, cruel fate!
But back to the topic, this is so cute... I honestly am blushing over it, and I am/my pony OC isn't even relevant in all this!!
Yeah, the way everyone is shipping them, It's only a matter of time before you see Mandopony next to Wildfire in an episode. Speaking of which, they should have a sweepstakes to have an OC put in the background.
Like? I hear this all the time but I never get a specific answer. I know Sibsy is kind of a special case, but her OC was put in the show; with my extremely limited knowledge of legal matters, I'd figure there could be some way to make that work for others.
Oh god, you asked a legal question. This might take a while to explain...
Sibsy's made it into the show only because she's the senior storyboard artist for the series. Actually anyone who works for Hasbro or DHX could find their OCs (if they have one) placed in the show, since according to US and Canadian copyright law, all employees must relinquish intellectual property rights to their employer as a condition of employment. That goes for any industry, really, but working on MLP makes the intellectual properties much more publicly visible.
The problem with taking, say, Mando's OC or Pen Stoke's Nyx and putting them in the show (thereby making them canon) is that local copyright law doesn't explicitly cover intellectual property rights for entities NOT directly or indirectly employed by the copyright owner. That's why no one can force Hasbro to go after all the "deviants" on here that have posted images of their OCs. They're still, technically, the intellectual property of the individual artists.
Hasbro has stated repeatedly that the only reason it moves to take down possible copyright infringements for fan-made MLP work is because under US copyright law (which, I might add, is just as ridiculously written as the rest of US Code), if they don't pursue EVERY potential infringement, then they forfeit the right to pursue ANY infringement in the future (because the US legislature is run by packs of rabid monkeys). Hasbro doesn't WANT or even TRY to pursue these things, because it's proved itself to be an incredible and free form of advertisement.
tl;dr 1. Wildfire (Sibsy's OC) made it into the series, because anything MLP that Sibsy creates is technically the intellectual property of Hasbro. 2. Mando's OC (or any other fan-made MLP idea, including shipping pairs) can NOT make it into the series, because those ideas are technically the intellectual property of the individual fan artists. 3. The few tips-of-hat in the series to the fans (Derpy, Dr Hooves, etc.) are considered "referencing" (US Code) or "homage" (Canadian Code), and are considered too widely-adopted to be the intellectual property of any one individual or corporate entity.