Top Plate/Sea Eagle aka Type 382 should have more than enough range to support HHQ-9, given its 300km search range for the Type 382. Do remember it is the search radar used for ships that employ its Russian counterpart, the RIF-M, including the Type 051C and the upgraded Slava class cruisers. Slavas also use the Top Plate's predecessors, Top Pair and Top Steer. Its more the question of the fire control radars --- Tomb Stone or Top Dome --- that is needed to support the RIF-M --- but they are quite big and inconvenient for a smaller ship. However, if the missiles are actively guided, you don't need the fire control radars.
In terms of size, HQ-16 is the equivalent of the SM-2, both being 700kg sized missiles. Not only do they weight similar, but they also look similar and share the same wing configuration. Not saying the Chinese copied the Standard for the HQ-16, the HQ-16 is copied from the Buk, which is likely copied from the Standard. Why does the Standard has better range? Most likely from the target illuminator that has greater range (SPG-62 vs. MR90 Front Domes) and possibly extended burn propellants. I would think there is certainly room to stretch the range of the HHQ-16 here. Simply going with active radar homing, it could both increase the missile range and simultaneous target engagement capability of the 054A without any external add ons to the ship other than software changes in its fire control system.
HHQ-9 is more the equivalent of the SM-2 ER in terms of weight, both over 1300kg, or nearly twice the weight of the SM-2 and the HHQ-16. If HHQ-9 uses active radar homing, then its closer to the SM-6 which also features the same and also on the same weight class. But it lacks the SM-6 limited anti ballistic missile capability.
I should mention that the current trend for next generation of Western frigates is moving away from the Standard and into the ESSM as the main SAM for the quad packing, with the SM-2 being the option. Quad packing would still favor using the U-VLS over the AJK-16 for future Chinese frigates however. Only ESSM Block 2 would be used due to being active radar homing, and with the lack of target illuminators, any use of SM-2 would have to be the upcoming block using active radar homing, which means legacy support would be lacking. I would say that active homing SAMs --- whether its shorter, mid, or long range --- should be where the future Chinese frigates must be using, and its not about the range but the technology.
With regards to seeing signs of the 054B, nothing yet. Furthermore, one of the major frigate builders, Hudong Zhonghua, is going to be preoccupied building Type 075s for a while, unless they decide to build the 054B right next to the 075. But seeing that they might build two 075 next to each other makes building the 054B unlikely for this shipyard until the 075s are done and they don't plan to build more 075s. But seeing the mast and radars on the Type 075 might give a clue to the 054B.
The other shipyard, Guangzhou Huangpu --- confusing name since this shipyard is not anywhere near the Huangpu river, which Hudong Zhonghua is --- is tidying up finishing the last Type 056A from its contract. What goes next for this shipyard is what we need to see. But we have not seen any leaks on this shipyard for a while, and you cannot do aerial on this shipyard since the ships are built inside a shed and not on an open dock like Dalian.
Based on current ship design patterns on the PLAN, the next Chinese frigate would have to adopt the configuration where a Type 1130 CIWS would be set in front between the VLS and the bridge and the HHQ-10 launcher would be set in the rear above the hanger.