Chorus and flanging are types of delay effects so in this case they're using the same delay engine for multiple purposes.
StereoDelay.Ax is only** available as a 32bit DX so any plugin using it wont show up in Sonar 64 bit.
**If it is available as a 64bit DX then they may have stopped including it with the current version of Sonar.
I just remembered on my current machine I didn't bother installing any of the previous Sonar versions.