ok, here it is:
q1) 4 but 132 if all maharajahs are considered unique.

q2) 40 by placing all on squares of one color.

q3) I have two answers, one is nicer than the other, but both are less than 6 moves.

1. Bb5 black plays either c6 which allows 2. Be3 Qe5 3. Bd4 and white captures the Q or N next move due to the skewer. Or: 1. Bb5 Kf8 2. Be3 Qe5 and the game ends the same way.

Originally I thought because of 1..Qa5 2.b4 Bxb4 and white can't take back with axb4 but now I see the forced win too, which is pretty: 3. Bxf7!! now if Ke7 or Kf8, 4. axb4 wins the Q or B next move, if Kxf7, 4. Qf3 Bf5 5. axb4 wins in the same fashion a move later, and if 3..Bxf7 we get the same theme with 4. Qf3 Of course 4..Nd7 allows the R to take N and 4..Ng8 or Nh7 allow the win with 5. axb4 where white wins Q or B next move.