Implausible - what pilot wants to live in the boonies when they could be flying a plane from a base near a city with attractive young women who might be impressed by a pilot?
Sod the technology - there are things you can do, but they aren't what matters.
Decide what capabilities the forces need. Build enough kit for realistic exercises. Use the combination of capabilities and outcomes from the exercises to build doctrine. Train the trainers.
The one campaign the UK...
As true as all of this is, the UK is from it's own internal perspective hard-pressed and skint. This isn't Shipshape, they don't know how much worse it could have been; and both the US and the UK know the US will have bigger forces in due time, even if they're not there yet.
There have been substantial routine imports of food to the UK since the late 1600s at least - eggs and pork products initially I think - so we're on several centuries on the trot of it being most profitable to import food whether or not it's necessary.
The OTL Japanese assault was on such a shoe string, I'd be surprised if they succeeded the same way TTL - but there may well be a scramble to reinforce for Round 2, rather than a British victory that actually throws them out of Malaya entirely.
British strategy was to fight using money and industry rather than men, wherever possible.
Supplying the Soviets with weapons to kill Nazis with weakens the primary enemy of the UK without also killing British soldiers in the process.
Debating numbers and priorities is valid, but the basic...
France was fairly mobilised, but had ~120 divisions from a metropolitan population of 41 million. I don't know off hand how many of those divisions were colonial.
Oh, I was assuming "once a fresh offensive is on the cards". Hard to imagine another few hundred miles on the bounce when they've already gone well beyond the plan, this is the British Army not the IJA!
Yeah, I think it's entirely understandable that de Gaulle gets a bad rap and also hard to see what else he could have done given the situation he was in.
The US and UK OTL both used their influence over food supplies and North Atlantic convoys (U-boats don't know which ships are aiming for Spain!) as the stick, and high prices for Spanish exports (especially rare ores, I think tungsten?) as the carrot to keep Spain neutral.