Tools like melodyne ect can be useful,
So much reggae is already in a min key, perhaps some marley tracks might sound okay with changed harmony ?
The thing is though, if the song contains too many chords it might not sound right in a certain key.
Beatles tracks made great use of chords & the changes to a certain min chord within a song added greatly to the feeling.
The bottom line is trial & error, at the end of the day, if it sounds good, it is good.