The Unlimited Data option in your Build-a-Plan bundle applies to all servers available to you. This includes all the Pro location in your bundle as well as all the Free locations you already have access to.
In addition, when purchasing Unlimited Bandwidth and R.O.B.E.R.T. under the Build A Plan umbrella, you will get access to a total of 10 custom rules for R.O.B.E.R.T. DNS filtering alongside access to all the R.O.B.E.R.T. DNS blocklists.