Could this be an air launched AShBM?
Isn't the Iskander a ballistic missile vs Kinzhal is a cruise missile? I'd imagine there are significant differences.The DF-15B has similar or better performance than the Iskander which is allegedly the basis for Kinzhal.
I think it is highly likely the Chinese did the same thing and repurposed a similar missile.
But the DF-15B is a lot heavier than the Iskander so I wouldn't be surprised if they had to change a lot of things in the design.
The fins could have been removed or redesigned. An air launched missile will have a different flight profile than a ground launched missile too.