Normally Firefox and Iceweasel use the same configuration folder (~/.mozilla). Are you using the same profile for both? I have the same setup (Oracle jre and jdk in /opt for use only when necessary). My java version is this:
~$ java -version
java version "1.7.0_65"
OpenJDK Runtime Environment (IcedTea 2.5.2) (7u65-2.5.2-4)
OpenJDK 64-Bit Server VM (build 24.65-b04, mixed mode)
Restarted FF, even the OS (been tackling this a while) and still Java website reports no java plugin?
I went to the Oracle website and then to Java in the Products section. Everything seemed to work normally. Can you tell me where you got the information about the java plugin on the "Java website"?