Spring is not built into WebLogic, so that's something that you will have to provide as part of your deployable WAR.
As far as JSF pollution goes, that's a very real problem. One of the primary differences between the old
J2EE standard and the newer JEE standard is that in JEE, JSF is a built-in capability. Thus, there is a copy of JSF built right into the WLS server.
If you include JSF libraries in your webapp, there will be at best version conflicts and at worse severe classpath data issues, leaving the application (and possibly the server) corrupted. Results are totally unpredictable.
The job isn't made any easier by the fact that a lot of what's published on the Web is either older (J2EE-based) or
Tomcat (limited JEE) examples. Tomcat does not include the full stack, neither JSF nor EJB nor a lot of other JEE-standard things, so that makes it necessary for Tomcat WARs to include libraries that full-compliance WARs such as those used by WLS do not.
The best place to resolve issues with JSF JARs and components is in the WebLogic documentation. It will tell you how to properly define a webapp for the version of JEE that it supports as well as overrides if
you should find it necessary to ignore the built-in JSF and use an alternative implementation.