No you can choose a-la-carte.
Using Camel + CXF deployed as WAR files in WebSphere is a great solution.
ServiceMix / FuseESB is a ESB server (eg has start/stop scripts etc.) where as Camel and CXF is libraries (eg just a bunch of JAR files). Fuse ESB provides Camel, AMQ, CXF and more out of the box, all integrated together.
So in your use-case I would go for Camel + CXF deployed as WAR files in WebSphere.