Malamar

My opponent has Malamar with the "Contrary" Ability in the Active Spot. On my turn, I attach Blunder Policy to my Fuecoco and use its "Spacing Out" attack and I flip heads. The coin result will be treated as tails, but since the physical coin flipped heads do I get to draw 3 cards with the effect of Blunder Policy?

There is no distinction between the actual result of the coin flip vs. what the outcome is treated as. Regardless of what the physical coin shows the flip was tails, so you would get to draw 3 cards from the effect of Blunder Policy.

What happens if my opponent has Malamar with the "Contrary" Ability active and I play Will?

Will lets you choose the first flip for an attack as Heads, but then Malamar's Contrary will treat it as Tails.