I think a sticking point with China will be whether to press for the max RoC and let Xinjiang go, or accept less for Chiang to get a new allied state.
The Tibetans i think would support the UN recognizing the rebels to better secure them against possible Communist aggression in the future.
Keep in mind, while the Un forces have won it has been insanely costly on the heels of WWII in men and material. And the West doesn't know how badly off the USSR is. For America there is also now the civil rights conflict gearing up, and the European colonial powers have their won issues to mind.
So the PRC will survive, ad with Moscow in shambles they won't get quite as bad a deal was they would otherwise. For the USSR and PRC their future will hinge on ow well their post war leadership is able to recover from the half generation of war.