For question 1), you can attach multiple Input Data nodes to a modeling node (or to a Control Point node then modeling node as you mention), but you can only have at most one data set of each role connecting to the modeling node. So you can have a data set with the Role property set to Raw or Train in the Input Data node, one with role Validate, and one with role Test all feeding into a modeling node, and the modeling node will use the data sets according to their role, score each one, and export the scored versions to subsequent nodes, keeping the same role. Hope that makes sense and helps.
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