Suppose someone recorded a song in 2001 in a specific studio, then they recorded another one in another studio, but because of differing microphones, reverb settings, mixing, and so on, they sound quite noticeably more hoarse in the second, can that difference be explained by just the different mixes alone? And can the 2nd song be edited to be like the 1st, and vice versa?
Literally billions of different variables make those recordings sound different, therefore there is no simple way of making them sound the same.
If their voice sounds hoarse on one and not the other, that has nothing to do with anything audio related. Purely the singer's voice.
Yeah. It’s funny how often this happens with just a few days in between takes when someone wants to change a part or lyric. The recording chain can be untouched and literally the same. And still you realize you need to track the whole song if you need consistency.
You can get them close but it will never be 100 percent. Just make them reasonably similar and go with it
EQ-Matching plugins are a thing, but they don't match reverb.