I can use the module design PrimeFaces in a proyect
Yes you can include jar files, for example libraries.
You can see this thred in the forum with details
Yes, if you have a predefined .jar, you can to import in WR. For example, a .jar that manage json estructure.
And use some kind of jar??
No you can´t use primefaces. But with webratio technology you dont need this aspect is transparent to developer.
No, Prime faces is for .jsf technology, in WR works with Jsp.