Well, in light of Admiral Harris and his comments, here are my thoughts.
IMHO, China has planned very well, built up its resources, and then waited for the appropriate time according to its own time table to strengthen its position in the SCS.
I believe China would have done this irrespective of what small efforts Vietnam and the Philippines made....and also whether Obama failed with his "red Line," in Syria or not.
China is steadily and carefully working towards its own time table and accomplishment of what it feels are in its national interests.
The Philippines has little resource to attempt anything even minutely comparable.
Hanoi knows it cannot match China at all either...but it is not trying to. It's efforts are based on what it can accomplish, what resources it has, what defense it is building up, and what support it thinks it may get. It is not going to confront China.
More likely, it is simply seeking to strengthen what it already has in conjunction with what I just mentioned...IOW, within the scope of what it can accomplish given its resources, its own military, and the minimum support it thinks it might get, Vietnam is simply trying to solidify what it already has so it can best defend it if necessary.
Admiral Harris is stating things from a US perspective which knows it cannot do a thing to stop China's reclamation efforts on those positions it already occupies. He seeking to punctuate the US claims and desires for free navigation and trying to establish a warning in that regard. What he has said is true...if it came to it, the targeting of those fixed locations would be locked in.
But unless the US is prepared to occupy or completely cut off those islands...then that ultimately accomplishes little, and would only lead to a full scsale conflict in the SCS. In other words, unless that already happens, the US would not act in that regard.
Sansha and then the three principle islands in the Spratley area are all going to be mutually supportive, and very much supported by the mainland...reaching down through Sansha. The US would have to fight an all out war at sea to try and prevent that. The US, IMHO, is not only unprepared to do that...but they have no compelling reason to do so.
China knows this and it not likely to suddenly stumble in its careful planning and do something foolish as to make a pretext for it.
The fact is...with the positions that they have established and are in the process of completing...and the influence it will give them....they are going to be in a position to offer to work with Hanoi and Manila to find ways to help all who are willing to economically benefit...but doing it on terms favorable to Beijing.
The one island shown that Hanoi is improving, and anything that the Philippines can do with that cargo ship on the one reef will not mean a thing to any of that. They amount to knits on the back of an elephant...ot tinkling in the wind.
China has already put in place...very rapidly and with a huge, planned expenditure of resource...the position and facilities to establish itself exactly where it wants to be in the SCS. I do not see them suddenly going wild eyed. They will simply continue and make use of the position they have established and proceed now from a position of strength.
I expect once all of those islands and bases are completed with their infrastructure...and an influx of more equipment and personnel, that they will offer the velvet glove to any of the nations that want to take it, and help meet their own resource needs, while providing benefit to those who accept it.
That's what I would do with such gains.
The US will ultimately maintain its desire for freedom of navigation through there...but China will have a vastly improved position at the same time.