My experience is that of the last post in the thread you referenced, it just worked for me, using OpenSUSE packages. I didn’t have to get any extra packages or install anything specially. All of Firefox, flash-player and nspluginwrapper packages are from OpenSUSE.
Just accepted the standard ones in the default install. I didn’t choose any special configuration, just a KDE4 desktop. This was a vanilla installation. I didn’t use any of the third party repos until I did a one-click install of “restricted formats”. Flash was already working before then, and inspection of the installed RPMs show that they come from OpenSUSE, not any of the third party repos.
I’ve got Flash and Real Player working on my machine now. I followed the instruction given here
While installing the nspluginwrapper rpms from the command line, I got a message saying linux32 package was needed. I remember that Yast would not install this.