I have an Unreal Project where both Mixamo Characters(Mixamo skeleton) and Unreal Mannequin Skeleton based Characters are spawned in a scene.
The Mixamo Characters have their own Animation BP(same event graph as Third Person Animation BP) and the Unreal Mannequin Skeleton Based Characters follow the Third Person Animation BP.
The Mixamo Characters and their respective animations have been taken from mixamo.com, I have created a few 1D blendspaces and Animation Blueprint in UE 4.25.3
The Mixamo Characters are moving forward after playing the stand-sit animation while the UE Mannequin Characters are in their own position.
https://gofile.io/d/JaCtUR (mesh , animBP, skeleton, blendspaces and animations)