Solos 1 and 2 feature the A natural minor scale (A B C DE F G). The track is in the key of A minor, so no surprises there. Solo 3 is more interesting, harmonically speaking. Guitarist Buck
b3 Ab Dharma plays the F Lydian scale (F G B C D E) over the F minor chords and the G Phrygian
Ab Eb dominant scale (G B C D F) over the G7 chords.
b3 F Lydian is the fourth mode of the C harmonic major scale. G Phrygian dominant is the fifth mode of the C harmonic minor scale. The theory is deep but you can still get a lot from practising the scale patterns shown here and improvising over solo 3.