In the video on the commissioning of Fujian, Xi was talking to a pilot who identified himself as a test pilot. I think the presence of test pilots and prototypes seem to indicate the preparation of flight instruction manual, procedure and protocol of J35 and KJ600 is still ongoing. May be they need to verify the validity of the beta version instruction manual on actual post-commissioned sailings. They may need a lot more flights and also pre-flights and post-flights, may be a few hundreds more flights, to iron out any possible bugs.
Just my two cents.
It somewhat goes without saying that the initial part of CV-18's service will involve creating and refining the TTPs of CATOBAR operation as well as integrating their new aircraft types (particularly J-35 and KJ-600) in a general combat ready state.
But the presence of a "test pilot" doesn't necessarily mean anything -- after all, there are "test pilots" and then there are test pilots.
For an aircraft carrier of such a new type with new aircraft types, even regular frontline pilots operating these new aircraft at an in-service capacity would be considered a "test pilot".
OTOH, if it is a test pilot from actual earlier stages of development and testing of any of the aircraft, then chances are it is just having an opportunity for an experienced aviator to be present at the prestigious commissioning ceremony (real test pilots for developmental phases of new aircraft programs are often quite experienced and highly competent in their field after all).
... Putting it another way, the presence of the pilot (regardless of whether they were a "test pilot" or a test pilot) shouldn't really change the baseline expectation for CV-18's initial service and airwing development.
