I think it needs to be said that the challenges involving weapons is easily one of the more frustrating challenges in the game. Beyond the weapons that are typically started with, the rest require either extreme luck to get if you use the Fiesta mode, or you have to roll the dice in hoping other people are not after the same weapons as you are on the map. If nothing else, please try to rework the challenges in a way that doesn’t feel obstructive to the actual gameplay.
For example, weapons like the HMG from the vehicles, AR, Bulldog, Commando, Disruptor, etc, would all count if you have them in the Automatic category. The BR, Sidekick, Sniper, Stalker Rifle, Shock Rifle, and Skewer would all go into Precision weapon kill categories. The Sword, Gravity Hammer, and default melee would count towards melee kills. Then Cindershot, Rockets, Hydra, Ravager, Grenades, Fusion coils and even Needler would count towards explosive weapon kills.
There you go, 4 weapon categories that are broad enough to incentive specific styles of gun play, but it doesn’t bottleneck you from making zero progress if the weapon in question isn’t in that list since they exist in ALL maps.