Frank gets impaled just above his knee with a wooden stake. Once the stake is removed and the leg bandaged, he walks with only a minor limp and even outright runs at points, when his leg would be incapable of supporting his weight at all.
Unless Abigail had recently gone on a murder binge of truly epic proportions, it would be impossible for all the dozens of bodies at the pool that Sammy falls into, to be all so fresh, and for all of them to be seemingly in the same state of decomposition specifically if they have been sitting in a pool of water. However since Lambert was also at the house and it appears that the property has some history for Lazar, it may be that they and other vampires use that house as a "dumping ground" for other bodies, rather than leaving the bodies where they died and risking attracting attention.
When Abigail is loaded into the van after being kidnapped and drugged, Joey checks her pulse, as Abigail is a vampire, and therefore deceased, there would not have been any pulse.
Sammy watches the Woody Woodpecker cartoon, Pantry Panic (1941) in her room, and judging by the audio, the cartoon order seemingly jumps around at random.
When Sammy falls in the pool of deceased bodies and climbs out, she is seemingly fine and thereafter. Were they truly rotting corpses, a person being exposed to that would surely catch some illness.