To aid me in thinking on this, do you envision this as a 1:1 mapping between service and port? For example, REX smart-proxy on 9000, template smart-proxy on 9001, registration smart-proxy on 9002. Or is this a microservices behind the scenes with a single web interface and single port?
Making a note that another RFC just opened plays into some of these design considerations and discussions happening there: Infrastructure roles