This is not about "identifiying a chord". The chord is already identified. This is about how a chord can be replaced with another, changing the flavor of a song. If I cannot ask here, I don't know where could I find useful advise.

I have played the rythm guitar on an amateur band and we performed "Sweet child o'mine" from time to time.

One point of debate inside the band, was the fourth chord in the main solo (Emin/Cmaj/Bmaj7/Amin). I'll not ask "what is the chord??" But take the following as background:

The most musically studied guy in our band, was the bassist. According to his theory, it has to be a minor. More or less on the same line of the following analysis: https://www.guitarmusictheory.com/sweet-child-o-mine-guitar-solos/

Lot of basic tutorials also consider this chord to be a minor (Justin Guitar to mention one)

I have seen a lot of partitures for this song. Some captures of the discussed part:

So, according to "some" theory, it is a minor. Period.

But despite all the previous theory, my ear is liying me and telling it is a major. Well, it is a power chord for most of the time. Why my ear is filling it with the major third?

I have also analyse some of the solo fragments of that beat in partitures. It mostly avoids the 3rd interval, but it plays the minor in very quick parts.

Seems like D chord transposed to the 7th freet.

The following tutorial also uses A major:

My question is not to ask for the "real" chord here. It is more or less clear that it will work with major or minor.

I want to understand, instead, what is the theory, if any, that could explain that the rythm plays major third but the solo uses the minor?

For me, when we use Amaj, the solo has a bluesly flavor. When we use Amin, the solo has an arabesque flavor. Can be that an acceptable explanation?

And sorry for the lengthy introduction. I just tried to put all the possible data.