Why Mittens and Mickey Mouse?

Let's address this thing real quick.
Mittens was chosen for localization because:
- The character has cat-like traits.
- In Japanese, ミケちゃん (Mike-chan) references (as a nickname etc) 三毛猫 (Mikeneko - Calico cat).
- You can actually google ミケちゃん and most results will be cats lol
- Mittens is a common cat name in English, allowing English speakers to (hopefully) make the same connection as Japanese speakers.

Mickey Mouse was chosen for localization because:
- In Japanese, ミケ太郎 (Miketaro) combines ミケ (Mike - her nickname) and 太郎 (Taro). Taro is a suffix usually found in male names (often meaning eldest son). When used for a female, it acts as a playful tease.
- In English, ミケ (Mike) could be localized in a few ways (Miké, Mickey, Mikke, etc.), but 太郎 (Taro) doesn’t have a direct English equivalent.
- To capture the teasing intent, we needed a way to make Mike sound annoying. Since the character looks like a cat, calling her a mouse would be a purrfect way to irritate her. And what famous mouse shares her nickname? You get the idea. It helps Mikey is male so it also kind of works in a sense of taro being male suffix originally.

The obvious issue here is that you lose that connection of Mike(-chan)+taro because of the mittens localization,
but considering her name is Miketa, I think it's still pretty clear.
Neither of these choices were made just because we "felt like it."
They were selected to preserve the original meaning.