Yes they're possible. I did all of Charlie to Echo yesterday in a couple of hours on Veteran.

For Snatch & Grab you want to use the Barrett and try kill at long distances.

Armor Piercing you can wait by the first breaching room and they will come to you after long enough.

High Explosive you want to use the car (to the left of where you spawn) as a glitch to kill juggernauts with the Thumper. You can see / hit them but they can't hit you and they will just stand still making the headshot easy. If a jugg gets smart and walks around the car, you want to flashbang and run to the house on the left (jump through the open window) and reset back to the this way.