With no FC-31 derived plane in sight yet, it's pretty much a given carrier 003 will be using exclusively J-15s, for at least first few years of its existence. And given that any production ramp up of a whole new plane type is slow, it's likely 003 won't have an air wing with less than 50% of its planes being J-15s for another few years. Possibly not even before end of this decade.
So, given that the batch 3 is evidently similar to previous batches, we can expect the more visible changes only on batches meant for 003. Which would HAVE to be catobar variants of J-15. Otherwise, what's the point? They're certainly not going to be using 200 m of the deck to take off, without a ski jump ramp. (I guess it's still theoretically possible 003 will feature a ramp, but let's not go there)
I would expect the batch 3 to be pretty large. And followed by batch 4, possibly, as well. For two carriers, something like 150% of their combined plane numbers would have to be available. So some 70 or so of these basic J15s. Before production switches to a different J15 (catobar variant?)