I'm a little confused about what a "monocolored creature" is.
Defiler of Souls is definitely not, having a mana cost of 3BBR - Black and red is definitely not monocolored.
Birds of Paradise definitely is monocolored, having a mana cost of G.
Soulfire Grand Master has a mana cost of 1W - this is where my uncertainty lies. Is this a monocolored creature because of the single (W), or does the (1) disqualify that?