I'm tossing a season 6 label on this just in case people consider background ponies to be spoilers. Weirder things have been spoilers.
When I first saw and heard Angel Wings in "Top Bolt", I had the feeling that this was going to be the case. She is slightly different than your typical backgrounder, and fangirling over Dashie and Twilight is something a lot of us would probably want to do. Turns out there was a reason for it. A quick query over to Big Jim on Twitter revealed the real story.
Just like Stellar Eclipse from a few years ago, DHX has scooped up another kid from the Make-A-Wish foundation. Angel Wings was an actual little girl and fan of the show. And considering giant bows are the best thing ever, I can't complain at all.
We apparently have one more on the way, most likely in season 7 (coming in spring!). Keep an eye out!
Whoever it is out there, get some bat wings on there!