Fighting game scaling

Hello everyone 2 questions.Im using blender into ue4.What should be the scaling for the characters into the ue4 world.Dose the size of the world and objects in the world effect the memory and effect how fast the game move?.
I have some fbx file characters for other fighting games and when i import them they are small in the blender space.

1 Unreal Unit (uu) = 1 cm. The scale should not make any difference in terms of memory requirement, only texture resolution, Mipmapping- and LOD settings, polycount and number of materials.