Looks like I'm going to need to post this exact message for the 3rd time.
The portion of the 3DS hacking community is extremely small, so an extremely small portion of the entire community will be playing the leaked copy.
The hacking community and the FE community are not exclusive, so most definitely will likely buy the game on release anyway.
There's no Japanese 3DS hacking community, so its literally not going to happen that this leak will hurt JP sales of SoV.
3DS hackers who are playing JP SoV still can't enjoy the story, which was a huge draw to this remaster. And all those I've spoken to are in fact more intrigued by the game now.
On Emulation: Citra barely runs Fates, let alone runs it efficiently without a god-tier PC. The most FPS you can get from SoV is reportedly like 10-20 frames ALONGSIDE a ton of graphical bugs. It's also in Japanese. You can't emulate 3ds games like VBA. You can't. Citra is not there yet and won't be for years. Unless you're a masochist who wants to play a foreign language game with absolute garbage FPS, emulation is highly likely not to be enjoyable at all.
Fire Emblem Fates literally had a fanslation that had a menu patch, supports and all 3 main campaigns translated before the English release. It received negative PR, lukewarm reviews and was given a lot of flack. yet the game still sold amazingly in North America. Nobody is going to bother making a fanslation of a game like this scheduled to release in a month.
This leak won't affect sales at all and will keep building hype.