According to link you provide it is not possible to run multiple instances of Fedlet on the same instance of Tomcat:
You can deploy multiple instances of the Oracle OpenSSO Fedlet on the same host as follows: Multiple Java Fedlet instances can run on the same host server if each Fedlet instance runs in its own Java Virtual Machine (JVM).
So, you can not configure the same fedlet.war to be configured against an additional IDP. You may install on the same host additional instance of Tomcat (that runs on different ports) and configure its fedlet.war against an additional IDP.