Should you have the neck snap ability, this mission's first part will be immensely simplified. Otherwise, stick to the Stun Jack or the knife (the latter being useful only if your reflexes are very fast). The tricky part is on the last guard. He's watching security cameras, so wait for him to be distracted before you silently jump down. Drop him and acquire your weapons. Hit the switch on the door to open it, and head back upstairs. Kick open the double doors, and go to the balcony.