The key thing with standard harmonicas is to keep in mind that to get minors you often can only play 2 of the three notes, and sometimes only one, of the chord. You are implying the rest of the chord. You need to get the notes of the chords in your head to do this right. On a C harmonica, suppose you want Eminor, you can get E and G (2 of the notes for E minor (E,G, and B) quite easy (2,3 blow; 5,6 blow, etc). In fact, whatever you do on holes 2 and 3, blow or draw, you are in Emin (everything is an E,G, or a B). For an Am, you can get A (6 draw), and that is it there, except that the C,E of the chord are available together next door, (7,8, or 4,5) by blowing.
It is worth pointing out that on a standard C harmonica, your 4,5, and 6 draws are already Dminor. So, say you are in D minor, and suppose you want to find a Gm, for a blues, or just a minor song, the notes you need are G, Bb, and D (and an F if you want a Gm7). You can't get them all in one big draw or blow. So you have to find the note that best implies Gm in the song you are doing (you can only get a Bb by bending). And so on. Bob Dylan is an absolute master at this!!!!!yours, Peter T.