The 1st HK Fighter Squadron seems rather fictitious. Definitely overpowered, compared to the Japanese squadrons.
According to WIKI there were only 5 biplanes there,four of which were destroyed in the initial air raid. In testing several times, the initial raid onthe Kai Tak airfield always leaves the 1st HK Squadron as strong as or stronger than any of the Japanese squadrons.
I understand that this squadron may be included, even as ovepowered as it is, for gameplay reasons, but I'm guessing there will be some grognards who complain about it.