How can we add titles to key-in fields once user has clicked add button

Everything except the titles is copying over from the original code for the widget. 

You mean to say you want to copy the field labels too when a new set of fields is created on config list widget?

Example:

If this is what you want, this is possible with CSS codes.

Inject this CSS codes on each of the config list widget (since they all have the same labels). Paste it under the CSS tab.

th{display:none;}

td[class*="col"]:before {font-weight:bold;display:block;}

td.col1:before {content: "Client";}

td.col2:before {content: "Brand";}

td.col3:before {content: "Indication(s)";}

td.col4:before {content: "Duration";}

td.col5:before {content: "Role";}

td.col6:before {content: "Type of Work";}

td.col7:before {content: "Phase(s)";}

td.col8:before {content: "Audience";}

td.col9:before {content: "US or Global";}

Example:

Result:

Hope this helps!