Workaround could be to add the data of your custom dropdown to a hidden text field and then can use that data.

Remove the calculated property from the field. Make it readOnly to set the value and on the button click make the access to open.

Can you please share your form with all artifacts on google drive (vkatoch07@gmail.com). I will have a look into your form.

You need to put the script in the CarMake field "change " event

1. I would like to have the entries that the user enters into the rows to auto-populate into the text field or text box. Populate the text field or text box on exit event of user entered field.   2.  I also would like to have certain entries in the text field or text box to copy to the next table wh...

You need to change the "yourFieldName.access" property to desired value in button click event.   yourFieldName.access="open";

A quick check, to see if the fragments are not embedded in the Form.

Repeating data binding doesn't work for two tables/subforms with the same data node.   What you can do, for the first table you can do repeat data binding to populate the table. And for the second table, you need to populate the table with java script by traversing the data XML.

Need to check form

Is your form working as expected while you preview it with sample data?