The L-15 is significant; two future CATOBAR carriers (if true) would demand a large number of trained pilots
Regarding this bit, they spent a lot of time on trainers for CATOBAR, the idea being there are now much more options than before and PLAN is likely to try some of those options out before deciding.
Option 1: CATOBAR JL-10 (the one with twin tails, aka the little honey bee). This was the originally planned option. However given JL-10 relies on Ukraine sourced engines and the Ivchenko-Progress factory that built them is now a pile of rubble navy is having second thoughts about this option. Shilao describes JL-10 as something like Russian A-50 - very useful but hard to replace so desire to further work on them is low
Option 2: navalize JL-9. JL-9 was originally rejected for carrier trainer because being based on older MiG-21 design its fuselage is not as strong as JL-10 so can't handle the stress of carrier use, in particular it can't handle arrested landing without breaking. However since Fujian uses a new electromagnetic arresting system which is more gentle than the system in use on Liaoning and Shandong (J-15 pilots all speak highly of Fujian due to this apparently) navalized JL-9 option may be back on the table
Option 3: J-15ST. In earlier times while carrier trainer were being argued over a small number of J-15S was produced to be used as trainer until the proper carrier trainer could be settle on. Aside from cost these actually work pretty well as trainer. Given J-15DT is already a thing producing a CATOBAR version of J-15S would be just taking a J-15DT and removing all the EW stuff and should be pretty simple. Makes transitioning to J-15T easier too for pilots once they finish up training.
Option 4: simulators only for training. The option that USN took and there are also people in PLAN saying it seemed to worked out fine for USN so we could do the same and do away with the whole thing
Option 5: navalize JF-17B. Apparently the recent appearance by JF-17B at Changchun Air Show was not without reason. There's some interest within PLAAF to acquire JF-17B as advanced trainer. If that happens than a navy carrier based version may be possible too.
Option 6: J-35S. There's argument that looking forward a twin seat version of J-35 may be desirable to fill the same role for the navy as J-20S does for the air force, (UCAV controller etc) J-35's big hump even makes this version easier to make than compared to original J-20. If we zero in on this vision for the future then it may be worth it to go all in on a trainer version of of twin seat J-35 and use that as trainer. Makes transitioning easier for pilots go move onto J-35 once they complete their training.
Also, from what they say the future plan for vanilla J-15 is to replace them with J-15T even on Liaoning and Shandong and use them on land as land based training aircrafts. Since J-15T is just straight up a lot better and in any event PLANAF pilots fly J-15 on land bases land them just like as if they're on a carrier to ensure correct muscle memory, thus training air frame go through the same stress as carrier landing, so might as well use up the remaining life of vanilla J-15 that way.
They also said PLAN will look to test out Fujian in all sorts of combinations with 076 and the two STOBAR carriers as a group. So things like have the STOBAR carriers all use J-35 for CAP while Fujian focus on launching J-15T as bomb trucks. They joked that once 076 is in service that raises the number of individual em cat in PLAN service to four, thus equalling USN.