1. Eliminate PDF enemies (x7) with shotguns in under 10 seconds
You can do this during the menendez section of the mission quite easily as he starts with a shotgun and is practically invinvible. just chain kill 7 enemies fairly quickly and you will complete the challenge. The best places for this would be the first set of buildings in the map or in the courtyard of the villa at the end of Menendez’s part of the mission.
2. Eliminate PDF enemies (x8) with truck mounted MG
when you reach the villa as Menendez, you will see the MG truck park nearby. Head over to it and interact with the turret to climb on board. Mow down 8 hostiles with the gun to complete the challenge.
3. Rendezvous with Josefina in under 140 seconds
You’ll start the mission as Raul and as Raul you will be almost invincible. You will want to ignore all the enemies and sprint to the villa where Hosephina is located. Kill enemies if they get in the way, but don’t go out of your way to get them. Just follow the objective marker until you end the Raul part of the mission. Probably best not to attempt any other challenges whilst going for this one.
4. Eliminate Cartel enemy personnel with Molotovs (x12)
Just after you cross the river during the second part of the mission, explore the buildings to find an access box containing the molotov cocktails. Equip and toss! Kill 12 enemies with them and you will complete the challenege.
5. Crash an enemy truck
In the second part of the mission, you will see a truck coming right for you. At the same time, one of your squad will yell out to you to shoot the driver. If you can hit him, the truck will crash and the challenge will be complete.
6. Eliminate Cartel enemy personnel with mortars (x10)
You will find the mortars in an unlockable shed after you spot menendez for the first time as Mason. Use the mortars to kill 10 enemies to unlock the challenege.
7. Eliminate Cartel enemy personnel with machete (x10)
You will find the machete in the basement in a side room to the left near where you enter. Just melee attack 10 guys to death with your new weapon and the challenge will be done.
8. Locate evidence of CIA presence
At the very end of the underground area, you will come to a room with enemies burning evidence. Head around the corner to the right from the entrance to find this sitting on a desk. Interact with it to pick it up to complete the challenge.
9. Collect intel (x3)
Complete the mission without dying.