New Post: How do you indicate that a server role is just WFE (without Central Admin role) from the XML

That's not quite correct. The server "roles" are quite loosely defined and fluid in fact, but whether a server is a classic WFE or not is controlled by the following element in the XML:

<!-- As a general rule FoundationWebApplication - Start should never be set to "false", only either "true" for all servers, or a comma-delimited list of specific WFE servers.
                 *Note* if you want to remotely install dedicated WFEs in your farm (i.e. RemoteInstall Enable="true") you should name the servers here, in a comma separated list - e.g. Start="WFE1,WFE2,WFEx" -->
            <FoundationWebApplication Start="true" />

If this is set to "true", then ALL servers will effectively be WFEs, but if you specify one or more server names here, then only those servers will be WFEs (i.e. have the Foundation Web Application service started).

Brian