1) The point about the design is that power isn't necessary to cool the reactor, but there are at least 3 emergency generators. (Because of their similarities, the ACP1000 has recently been consolidated with the APC1000 design into the "Hualong One" and the exact details aren't yet available in non-chinese documents.)
I fail to see how the coastline of Fujian has any bearing whatsoever on a power plant in Pakistan.
2) It is, in essence, a standard pressurized water reactor with passive peripherials that don't need pumps. All PWRs can passively remove decay heat through natural convection via the steam generators. Those are where the heat ultimately has to be removed from. This used to be done exclusively by power driven pumps, but it can be done through gravity, if you have heat sink above the steam generator level. Which is what you have.
Engineers aren't stupid.
3) The question of hydrogen formation has been addressed at least since 1957 in the Wash-740 report. It is not new. All current designs include catalytic hydrogen recombiners from the start, which can reduce the hydrogen concentration below the point of combustion. (Combustibility is is a function of hydrogen concentration and water steam contentration. Steam will necessarily be released along with the hydrogen and render it inert for the time being, until the steam is condensed. Enough time for the catalyzers to work.) Unfortunately, older designs haven't been equipped with them in all cases, most notably in Japan - depending on local laws.
Furthermore, the containment itself is also cooled passively in at least some of the newer designs (not sure about the Hualong One). But as far as fallout is concerned, it is enough for the containment to remain sealed until the Caesium aerosols have settled within the containment. (The basic process is the same as with fallout outside the containment. But it is faster, because of the confined environment.)
This happens at a rate of 90% every 8-12 hours, if nothing is done. After one or two days, very little is left. If you use containment sprays (which also reduce pressure in the containment), about 20 minutes are sufficient to remove 90% of the remaining aerosols. (Another 20min will remove 99% etc.) That process is the reason why very little Caesium was released from Three Mile Island.
Unlike the small BWR containments, large dry containment can remain sealed for over 24h even if there is no cooling whatever, because of the much larger volume.