That was a rather quick clarification! According to director Big Jim Miller, the unicorn we saw in the trailer and the alicorn on merchandise shelves are NOT the same pony. In fact, thanks to some digging thanks to Whatshisgame the alicorn on the merchandise shelves appears to be an OC designed by Dana Reynolds called Evening Starlite which can be found here.
That clears up some mystery, but leaves a bunch of questions still unanswered. Guess we'll just have to wait for the premiere!
Thanks to Whatshisgame for the detective work and Murrisson for the original question!
Big Jim's Response
Twitter: Calpain