The Kashtan system on the 956EM Sovremenny carries a total of 72 missiles with a larger warhead than the HQ-10. However, it is a SACLOS system dependent on the Hot Flash fire control radar on the Kashtan module. I remember Rotorhead often derided it and claimed the missiles and guns got in each other's way. The HQ-10 on the other hand is fire-and-forget. If the Kashtan goes I expect it to be replaced by two 730 or possibly 1130 CIWS, which probably could be placed at the same position where the Kashtan is now, and a 24-cell HQ-10 launcher forward as in the origincal two Sovs. The Pozitiv radar on top of the hangar is also associated with Kashtan but I am not sure what could replace it.
As with the upgrades to the original two Sovs, the Sunburn and Shtil will almost certainly be replaced with YJ-12A and a VLS for HQ-16. I also expect the Top Plate radar to be replaced by Type 382, and the Russian torpedoes, countermeasures, fire control, and navigation radars to be replaced with Chinese systems, because these were all done before on 136 and 137.
Now supposedly the Russian Sovs have bow and stern thrusters according to russianships.info. If this is true of the PLAN ships, they are not tunnel thrusters such as the ones used on most PLAN auxilliary vessels because these are not seen in any of the photos taken in the drydock, so if they exist they must fold out from the hull like on the old USN frigates. If these thrusters exist I wonder if they will be retained? They would be useful for maneuvering but PLAN doesn't usually favor unnecessarily complex systems.