When Oliver and Felicity are talking about the gun men, they describe one as an African American while the gunman they are describing is in fact Caucasian.
Oliver controls 45% of Queen Consolidated's stock. The hostile takeover involves a rival working toward buying up the remaining 55%, following which they intend to hollow out the company. While 55% would give a controlling interest, many major decisions require supermajorities, and there are laws protecting minority stockholders from deleterious actions by the majority.
(at around 25 mins) Stunt man's face visible during the fight in the night club with Roy.