Here.
You can make your characters react to any physics by toggling the physical animation on and off and changing the profile at runtime to define different stiffness.
It reacts to things as you would expect - based on the PHAT asset collision definition.
It can also be improved by a control rig script now a days. Given that, and some engine knowledge you could force actions based on non physical behaviors at runtime with it too - so as to support older ways of doing things and make them work with the newer systems.
No need for any chaos vs physx bs.
The engine is what it is, and phys x will ventually be completely discontinued - as reported by ue4 staff more than once.
You should go with whatever will be avaliable in the future if you are starting now.
By the time you publish it, it will also probably perform much better than it does currently.
Forcing physx is going to cost you the ability to migrate and pick up your project later on.