Well, I don't think any of the PLAN's LSTs will be part of a true blue water capable ARG in the first place, however they still have a role in Taiwan and SCS contingencies.
And from what I understand, the main difference between an LPD and an LSD is that an LSD has a larger well deck than an LPD to carry more LCACs and LSDs also place less emphasis on an aviation complement.
As I illustrated in my last post, the 071 really combines a lot of the elements of both a LPD and an LSD. It has the large cargo capacity and aviation elements of an LPD, but also has a large well deck to carry 4 LCACs like an LSD.
So I can foresee a future PLAN ARG comprised of two 071 LPDs and a 075 LHD, with one 071 LPD doing the job of carrying the AFVs, and the other doing the job of carrying more LCACs and the variety of cargo and logistics vehicles.
It's also worth noting that the PLAN may not want to deploy the same kind of mix of amphibious assault ships as the US, and they may not even want to deploy the same kind of capability as the USMC. After all, at present and I think in the forseeable future, the PLAMC is not expected to fight a land war for extended periods of time like USMC, but as rapid reaction coastal and island assault/capture troops, and with limited inland direct action backed up by conventional PLA ground forces dropped off by cargo ships once shore and ports are secured.
Personally I think the PLAN should also look to build some of those smaller mistral sized LHDs offered for export, in addition to the Wasp/America sized 075 LHDs. I expect the 075s won't be built in very large numbers, maybe 3 at most, but I'd like to see the PLAN have a more distributed at sea helicopter component. The export LHD displaces 22k tons, smaller than an 071, and carries only 16 or so medium sized helicopters (Z-18), but is also big enough to carry probably a pair of LCACs or equivalent landing craft, and likely has the space for the command/control capabilities you'd expect for a ship of this size. I think if the PLAN had a good number of these medium sized LHDs, they can be used in a variety of roles such as ASW carrier, SOF carrier, not to mention having more ships for disaster relief, citizen rescue, and also to contribute to conventional high intensity air assault from sea missions. I expect the large 075 LHDs to mostly be relegated to conventional amphibious assault/air assault missions, and it would be nice to have some smaller, cheaper LHDs to do a variety of other missions during peace time or in lower intensity environments, but yet capable enough to contribute to higher intensity missions
I'd like to see maybe 6 071 LPDs, 3 075 large LHDs, and 6 of the export 22k ton medium LHDs, once everything is said and done.
I think LHDs are more flexible than LPDs for many of the missions the PLAN will want to do, and is especially important in a variety of Taiwan or SCS scenarios, where the deployment of AFVs and large amounts of cargo may not be as necessary as getting a number of flexible, fast reaction troops on the ground first.