Hi @Learn2019!
Glad you find it helpful. On KNIME Hub you can search for nodes, workflows and in future much more 
Haven’t checked in details but don’t see why wouldn’t it be feasible to use cross validation on workflow from picture.
No. Cross-validation is used for validating model and that is why in Credit scoring workflow you use Scorer node after cross-validation. Bottom branch is for model you will deploy - if it is the best at the end of course.
Here is another simpler workflow for cross-validation and corresponding topic from forum that can help.
If you will have any more questions don’t hesitate 
Br,
Ivan