I've read the latter part of the debate with interest & did a little research that might add something useful
1. Non-Self Governing Territories (NSGTs)
It appears that in the UN Treaty effective from 24th October 1945, that Articles 73 & 74 of the Charter Chapter XI addresses the international law regarding such territories as the Falkland Islands
Charter of the United Nations: Chapter XI: Declaration regarding Non-Self-Governing Territories
Article 103 states that the UN Treaty prevails over any other agreement
Charter of the United Nations: Chapter XVI: Miscellaneous Provisions
Britain listed its overseas colonies with the UN in 1946, one of which was the Falkland Islands, who were subject to colonial rule and government. It appears the aim of Articles 73/74 of UN Treaty is to free people from colonial rule to allow them to freely chose their own form of government and rule and to be represented by their own population - i.e. by the people, for the people, of the people. That's why the FI are listed
In 1960 the UN General Assembly passed resolution 1514(XV) which urges the Administrating Countries of NSGTs to speed up implementation of Articles 73/74
Resolution 1514
and in 1961 the UN provides for a Decolonization Committee for Administrating Countries to report on progress, with terms of reference given in resolution 1654
Resolution 1654
In 1965 Argentina raises the existence of its sovereignty dispute with Britain and the UN GA invites both countries to negotiate a peaceful solution which bears in mind:
a. The provisions and objectives of the UN Charter (legally binding)
b. Resolution 1514
c. Interests of the population
Resolution 2065
These negotiations are begun and a framework agreed but are famously terminated by Argentina in 1982, because it refused to accept the validity of a, b or c and argued they did not apply to the Islanders
As to the "how many" question, New Zealand via the UN applied Article 73 to the Tokelauns who are a population of c. 1400
Tokelau