As we still lack sites from the Pacific here is another original cultural development typical of native Chamorros. These variant stone constructions were a dominant motive in religious lives depending extensively on their purpose and natural settings.

The problem I have with this one is that the many of the stones have been moved to museums or Guam's main square, and as you say they were "Depending extensively on their purpose and natural settings"

Due to the recent inclusion of Nan Madol on Micronesia's T list (finally), I had another look on Pacific archaeology. France too added Taputapuatea at French Polynesia, which used to be a major spiritual centre for most of the Pacific Triangle. Then there are the Lepata sites on Samua, the Yapease quarries shared by Palau and Micronesia and two lesser known archaeological sites on Palau. All in all, a major improvement for this gap.
Still lacking - There was an attempt to include Pu'uhonua o'Honaunau on Hawaii which was deferred for the lack of comparative studies. It since disappeared. Anyone knows why?
We also discussed the Latte of the Mariana islands. It seems there are still quite a few sites in situ, not so much on Guam, but more on the Mariana Islands. Such examples are Taga and Mochong. http://www.wondermondo.com/Micronesia.htm These too unfortunately failed to be discussed for the new US American T list.
Discussing Hawaii and the Marianas brings me to another US territory - Does anyone know why no sites from Puerto Rico feature on the current US-American T list? We've already mentioned Caguana as a possible candidate.