Legolas is the geographically-closest “elf-prince” to Erebor, where the coat was found. But it’s made of mithril, and that can’t be found in Erebor.
So it was probably forged in Moria. The mithril was definitely mined there. We don’t know exactly when, but we know Moria bordered not one, but two elf-kingdoms (Lorien and Eregion).
Elrond was Gil-galad’s right hand elf, and probably could have claimed the title of high king after the Last Alliance, although he didn’t. He also lived in Eregion for a while, and met his wife in Lorien. He had two sons, both born well before Moria fell to the balrog.
Conclusion: it was forged either for Elladan or Elrohir. They wore it, outgrew it, and gave it back to Durin’s folk, who then brought it with them into exile.
Earendil was born in the first age so he wouldn't count but Elrond's kids for sure count. I'm not sure Legolas would count since we don't know when he was born. People assume he was born in the third age because of context clues but Tolkein never stated when Legolas was born.
Funny but not so accurate. We don't actually know when Legolas was born, we don't know that the mithril coat was actually forged in Erebor (it could certainly have been brought during the resettlement from the Grey Mountains), and we don't know what "some young elf-prince long ago" actually means and that none was born since the fouding of Erebor (I don't think we have an exhaustive list of noble elves from the text).