Whatever happened to the days...
...when Hollywood agents\managers or the people themselves changed their professional names to something either more appealing or pronounceable? Back in the olden days it was primarily to fit on a movie marquee, if ones own name was too long. Or if it was just simply unappealing. Example: Would Archibald Leach have been a huge movie star? Probably not. But under his stage name of Cary Grant he became one!
So in the golden age Kiernan Shipka would have been told to change it or actually been given a new name by the studio who contracted her with a "take it or leave" condition. But in today's day and age of who gives a damn, it's A-Okay to have a strange difficult to remember and easy to mispronounce name.
Yet notice that out biggest stars, examples: Johnny Depp, Emma Watson, Jennifer Lawrence, all have short and or easy to comprehend names.
Potential stars do themselves a serious disservice by keeping their non-showbiz friendly birth names. Hey, Natale Portman is NOT her real Hebrew name (for the record it's Natalie Hershlag! Oh and ever hear of Marion Robert Morrison? No but you sure have heard of John Wayne!)
Keirnan? How about Jessie Sales? Or Sarah Shore? Bad I know, but the studios had people hired to come up with stars names! (Though William Henry Pratt came up with his on his own which was Boris Karloff. And in music, Reginald Dwight decided to sing his own songs because no one else was so he became the much more dynamic sounding Elton John).