The thing is giving the Dutch Buffaloes in October/November 1941 actually gives them a much better chance than they had OTL. They got their Buffaloes right before Japan attacked - in some cases days before they were attacked. The Dutch pilots were horribly unfamiliar with the F2As and in the great majority of the cases had never flown any aircraft as
high performance at the Brewster. Giving them even 2-3 weeks let alone a month to familiarize themselves with the aircraft and you might very well see performance out of the Buffalo more like what the Fins saw against the Russians, and the Buffalo might be held up as one of the great little aircraft of WWII!
I also agree that having the British ship some Hurricanes to Singapore would make more sense than putting Buffaloes there. But that involves convincing Churchill to release the men and aircraft soon enough to get the pilots acclimated. OTL they did send two(?) squadrons but again they got to Singapore right before the Japanese attacked so they had zero prep time on site to be familiar with local conditions, which are just a bit different than northern Europe

and take some time to adjust to.
Tom.