No you cannot have 2 managed server in the same cluster that belong to wls installations of different OS.
You can check the same in
"Server instances within a cluster or domain can run on any hardware and operating systems as long as the hardware and operating systems are listed on the Supported System Configurations page at
http://www.oracle.com/technetwork/middleware/ias/downloads/fusion-certification-100350.html. However, note that running clustered server instances on different hardware and operating systems may impact load balancing and performance."
Thanks for you reply. That site was quite informative but I have a concerns.
Both Oracle Linux and Window 7 is in compatibility list, that means my case should work fine. Then why do you say that it will not work?
For clustered instances on different OS (even if the OS version is supported) this scenario is not supported.