There is always a possibility that they already designed it that they can switch out the canisters as necessary if the mission requirement is for anti-surface. For ASW, it is possible that these existing canisters are holding a few yu-8 rocket assisted torpedoes.
That's what I was thinking, except not the vertically-launched Yu-8 which would be launched from the H/AKJ-16 VLS tubes, but the Yu-11 which would be launched from slant launchers, though I'm not totally sure the latter is actually in service with the PLAN yet. I imagine the differences between the two would mainly be range and speed, with the Yu-8 (defensive-oriented ASW) being faster than the Yu-11 (offensive-oriented ASW), but with less range. I could see a use case for both being present in the same ship, especially one tailored towards ASW.
Let the destroyers deal with AAW, the frigate can hunt down subs. All you néed is a hull that has a sophisticated asw suite, a highly experienced sonar tech and a LAMPS type helo.
For an ASW-oriented ship it would have been better for the class to have a dual hangar, like the OHP frigates, which were also ASW specialists.
Consider me sceptical about ship-to-ship firing opportunities for light ascm fired from a frigate. Meaning, targeting a ship that can actually chew through a salvo reliably.
May happen, but not the primary use case really.
This is clearly a frigate meant to operate mainly as part of a CSG, so the most straightforward application of the frigate's ASCMs is as part of a saturation missile attack. The 054As will surely be more and more relegated to non-CSG/SAG roles as more 54Bs start rolling out.