For 嘎厦, see
(i) Kashag http://en.wikipedia.org/wiki/Kashag
(噶廈: pinyin: gá shà; was the governing council of Tibet during Qing Dynasty and Republic of China (1912–1949); set by Qianlong Emperor in 1751)
(ii) 噶廈 http://zh.wikipedia.org/wiki/%E5%99%B6%E5%BB%88
(d) Foreign relations of Tibet http://en.wikipedia.org/wiki/Foreign_relations_of_Tibet
(section 5 Period of the Qing dynasty; section 6 Period of de facto independence, 1912 to 1950)
(i) section 5 relies on the book:
Bell, Charles, Tibet; Past & Present. Oxford: Clarendon Press, 1924.
(ii) suzerainty 宗主權
The Xinhua article says, "But researchers on modern history and Tibetan studies claim the exact word the Dalai Lama used in this all-Tibetan declaration was 'region' (bodljongs in Tibetan) instead of 'nation' or 'country' which translated into 'rgylkhab' in Tibetan."
The "all-tibetan" is an adjective that means the document was written in tibetan language ONLY.