@Kana ^ this is the reason why you see a instead of the mii face. We cannot legally use the mii assets, hence it’s been replaced with in our open-source system archives. Please follow that guide and download the mii data from your 3DS console to get those faces.
We can’t do anything about that. Mii data is copyrighted, so we cannot include it in the emulator itself. Hence the no-entry sign replacement to make sure the game doesn’t crash.
If you’re short on cash, buying a second hand 2DS is usually the cheapest way to get one, or maybe buying it off of a friend if that’s an option.