At this rate the WS-15 will have the same as its American counterpart, the F119, only being used on a single platform and nowhere else.
The WS-15 can certainly be used on future iterations/developments of the more advanced UADFs once the production of the J-20 family is terminated (which won't happen before the early-2030s).
In addition, should the PLAN holds reservations about the VCE/ACE's reliability for powering the carrier-based J-XDT in saltwater environments, then the WS-15 would still see new users in the manned aircraft domain, at least for a period of time (similar to as of current, how the J-35 uses WS-21 instead of WS-19 and how the J-15T/DT uses AL-31 instead of WS-10H).
On the second point.- Across the lake, recall that the USN did mention something similar regarding engine choices for their F/A-XX sometime ago. So there's that.