The element name for the missing data must match the JSON node key in the Integration Procedure Response, otherwise the data will not be mapped correctly. The JSON sent from the Integration Procedure Action must match one of the Original Input for the Integration Procedure, otherwise the Integration Procedure will not execute properly. The Integration Procedure Preview Input Parameters and the Response JSON Path have no effect on displaying data in OmniScript.

Option D is the correct way to configure Additional input to send exactly the same data as Input Data. The Additional input should have the same key/value pairs as Input Data, and the value should be set to {{InputData.key}} for each key. This will pass the value of Input Data for each key to Additional input.

The Send JSON Path syntax for accessing an element from an Integration Procedure structure is BlockName.
ElementName. In this case, the BlockName is BlockX and the ElementName is ActionZ. The colon (:) is used to separate the input and output parameters, not the block and element names. The order of the block and element names should follow the hierarchy of the structure, from top to bottom.

Checking the Send Only Additional Input checkbox allows the Remote Action element to send only the key
/value pairs specified in Additional input to the Apex method. The Additional input should have the same keys as the method parameters, and the values should be set to {{InputData.node}} for each node. For example, AccountId: {{InputData.AccountId}} and ProductId: {{InputData.Details.Products}}.

In Preview, the JSON node that shows the data sent to the Response Action is the name of the Response Action itself. In this case, it is ResponseCart. The other nodes show either the input data or the output data of the Integration Procedure.