1)
You should be able to have more than 1, and to use data interfaces for two different components in the same kernel, you will need to create a “secondary input binding group”, which is right below “Primary Bindings” in the details panel. Pins in the same group should represent data from the same component.
2)
You can check the logic for how components are mapped in UOptimusDeformerInstanceSettings::GetComponentBindings(), as well as the UI logic for the dropdown in FOptimusDeformerInstanceComponentBindingCustomization::CustomizeHeader()
Basically the idea is that component bindings in a deformer can bind to any component in an actor. Firstly via the drop down if user specified the mapping, and secondly via component tags, which you can set on both the component binding details panel and the actual component’s in BP editor details panel.
Hope this helps!
Jack