It’s time for a very short Japanese lesson (I’m not even close to being fluent at all; only at around an N4-N3 level so keep that in mind). In Japanese, there is only one “co” or “ko”, written as こ in Hiragana, unlike English that has both of these options available. Many times, “ko” is used as the canon English version of Japanese names and words like neko. However, the official English name for Uraraka uses “co”, which is why it is best to write her name as Ochaco Uraraka. This is confusing because the Japanese manga site writes her name in English as Ochako.