wonder why they don't want to fully commit to using the Leopon girls' full names

cognizantmirai said:

wonder why they don't want to fully commit to using the Leopon girls' full names

It's their "soul name" apparently, a common theme in the GuP-verse (post #5177170). You can tell because they're spelled using Katakana, whereas their actual names use Kanji/Hiragana, so there's a special emphasis there. All of them are named after a famous racer from the real world, and it's probably the same in their world. Since they're all automobile enthusiasts, they're using that connection as a basis for their soul name, much like the history girls all have history-based soul names.