Rarity's ability to find gems is arguably similar, but they never did an episode about that. I think the only time it really came up outside of "The Cutie Mark Chronicles" was "A Dog and Pony Show". Maybe you could loosely consider "Dog", but it wasn't Rarity's talent that saved the day.

These connections are interesting, but I think the Sonic Rainboom was really much more pertinent to the overall continuity, given that it gave the Mane 6 their cutie marks and is shown to be one of her signature moves.

The Mane 6 being home to the ponies that have strange abilities like this seems to cement the fact that they're more than average ponies, and that they were destined to do great things for Equestria. All six of them getting their cutie marks at the same time seems to support that, and off of one of these aforementioned talents, no less. Twilight was left out because she already had expansive talents and abilities, and also the potential for more, and for Applejack, her family and her personality mean more than any physical attribute.

Otherwise, I'd think these were three random episodes that just happened to be similar to each other and no one really thought about the connection until you did 4 years later.