From what I understand about the Phys_Walking and setting an object to “base” status, means that when the actor collides with the “base” object, it is automatically alighned to it via the Z axis giving the illusion of walking on the surface. Perhaps in UE4 you would need to sting together something that removes effects of gravity from actor when collides with “base” object.
I really cant wait for the UE4 Platformer Demo in the Marketplace - I have high hopes that it will address some of these issues.