Again - perfect foresight would be required and had that existed they would not have needed the base anywayFive Years. Example is Pearl Harbor. 0-class II 1933-1937. Class II to Class I 1942-1943.
See previous comment.
Geography. See previous map? If one cannot forward defend north of Luzon, then the ONLY other naval geography that works is the Andaman Islands.
See map. See Thailand? Worry.
Never happen. EVEN under those conditions, the RN staff, judged their means to hand was inadequate in a straight fleet square-off. as in British battleships (their metric) were inferior to Japanese battleships and that the Japanese could bring an 11 to 7 (actually with the "R"s 11 to 5 based on speed gauge) surplus in offense/defense into region compared to what the RN could safely risk out of Europe. That is why from Backhouse forward, the British kept asking the Americans for "help".
The Japanese were no more able to concentrate their entire Battleship fleet in such a fashion than the UK and the USA was at that stage of the war
As for Thailand - not an issue until the Germans cross the Meuse and end France as a major power - the Thais are not jumping in with the Japanese, with Thailand effectively surrounded as they were by France and the UK and only jumped to the Japanese camp at the 11th hour (effectively the 12th hour as they resisted the initial Japanese invasion in Dec 41)
And the British have 'only' fought coalition warfare in major wars for 200 odd years ever since the Europeans ganged up on them in the 1700s (if not before) - of course they asked the USA for help.
Its how 'sensible' nations fight wars - WW2 was no different