Yes. The KAK LR-308 Lower Parts Kit will fit and function with your Warthog 308 lower receiver. The kit includes the mag release, take-down pins, selector, trigger guard, bolt catch, buffer retainer, roll-pins, detents, and small springs are included to allow completion. The KAK Mil-Spec LR-308 Lower Parts Kit also comes with a Mil-Spec Fire Control Group to ensure reliable operation and ignition of hardened rifle primers.
Yes this item will be compatible.
Most parts will fit an AR15 lower. The parts that won't will be the bolt catch, the bolt catch roll pin, and the takedown pins.