Your problem there is that the logic levers aren’t intended to be simulated, when you pick up the base of the suitcase it simulates the lid as well (they are auto welded), you can either unsimulate the lid OnGrip, unsimulate it on the main body dropping, or put a scene component between the two which will keep the lid from being simulated when the body is held.
You could also move to a straight physics constrained lid instead if you wanted to (using a manipulation grip on it).
Technically the lever should still “function” when simulated since it will directly set its location, however you appear to be forcing a manipulation grip on it instead of using GripObjectByInterface so its not using the CustomGrip type that it needs to be using (thus the spinning around hand physically simulated). The object specifically asks for the CustomGrip type with the interface, you need to be using it.
Edit I guess technically I could force unsimulation on grip on the lever itself, but generally it shouldn’t need it, in practice with a mockup it worked fine since it was still using the custom grip type.
As for grabbing an object from the slider itself case, the slider is its own grippable object, I allow gripping actors AND components on objects and child components cannot dictate the position of their parents. You can constraint two objects or add a second grip to the actor itself or use two actors, ect, there are multiple ways of doing it.
I don’t have a “pass grip up” feature built in that would force the parent to be gripped instead of the child if the child is set to DenyGripping currently, but you could easily add that in to your grip logic check. Its more of a user side thing, if the slider is set to DenyGripping then check its parent actor for the grip interface and grip it instead.
The angular limits part is essentially how the example gun was setup prior to me making it a slider, however I will note that the InteractionSettings got removed in 4.20 and put into a GripScript instead as they were generally far worse than just hand scripting a CustomGrip type.