You do realize you sound just like your buddy at Jane's that only count the satellite picture, right?
There is a difference between "can" (theoretically not impossible) versus "likely" and that difference is even more stark when considering the discussion is about engines which we always put into a higher level of vigilance.
There is a reasonable range of "plausible claim to be made" and talking about WS-15 as if the idea of it "can" maybe possess TVC is an extrapolation that is just on the wrong side of the fence in context of currently known developments and J-20A.
I understand people here are enthusiastic but I am noticing a trend where people see matter which are not yet clearly delineated or characterized or where knowledge is incomplete, and it is populated by suggestions on the more optimistic spectrum.