DO you mean things like the port numbers Tomcat will be using?
I have fuzzy indications that MAYBE server.xml can handle variable substitution, but ultimately server.xml IS a properties file. When running multiple Tomcat instances, you would normally split the CATALINA_HOME and CATALINA_BASE directories apart and keep a distinct server.xml in the CATALINA_BASE of each defined Tomcat.
Customer surveys are for companies who didn't pay proper attention to begin with.
subject: Read Connection details from property on start up.