The Executioner all I did is run around playing my usual style with PDW and anytime I found a clueless sniper/camper I pulled out my Executioner and headshotted them. Then just go to hardcore for the 150 kills no perks no attachments, people drop like rocks. Should be able to complete most of the double kills, revenge, bloodthirstys as long as you keep to small spaces to do your fighting.
Hardest for me was Assualt Shield by far... but I actually had the best luck in Domination due to the predictability of players and being able to flank them. I was getting completely raped in HC when I tried.
The Bloodthirty on Crossbow was a pain in the ass...finally completed that in a game of sticks and stones after trying all the other tips like FFA with Tri-bolt and scavenger or HC.
The next worst thing was the 10 player controlled scorestreaks with the FHJ. I suggest you all get your basic 100 aircraft out of the way and keep a class with black hat + FHJ + Cold blooded so that you can take out any Lodestars or VTOL warships. 9 of my 10 were Dragonfires and those are few and far between. Or when a Dragonfire finally shows up teammates shoot it down or EMP it instantly... The damn thing takes 2 shots from the FHJ or you have to shoot it with your gun and then lock on with the FHJ. So many times I locked on and was about to shoot and then got killed... it's maddening.