Looking from Aug 2020 to Aug 2021, theres a drop of 340 777 CNs. This coincided with a 140 increase on the 747, and a 50 increase on the airbus, and 27 on the 320s. It would therefore seem that the majority of the total loss of around 130 captains from all fleets came from the 777, either from retirement/ resignation. Id be expecting the 777 CN number to go down even further with more drafting to the 320 and the 747, and now with rumours that the 777 fleet is going to be reduced to only a small fraction of what it used to be.
777 FO numbers dropped only slightly comparatively by a number of 120. Interestingly this is also the total number of HKG based FOs lost from Aug 2020 to Aug 2021. This once again happened with a increase of 70 on the 747, but a drop of 30 on the airbus. (Will not be counting the 27 on the 320 as most of those are DEFOs from dragonair.) Therefore it would seem from the numbers that FOs spread more evenly from all fleets made up the total loss of 120 FOs between Aug 2020 - Aug 2021.
If you look at CN/FO ratios back in Aug 2020, only the 777 had a close to 1:2 ratio. Both the 747 and Airbus were closer to a 1:1 ratio. The current ratio of 1 CN to 2FOs on the 777 fleet somewhat makes sense if you think about the future direction of the company, which is to make the 777 the workhorse for high demand long haul/ ultra long haul flights, while leaving the shorter flights for the other fleets. However, considering the ratios of the other fleets and 2SO ops etc, I would expect that the company is planning to bring 777 FO numbers further down, most probably by drafting to other fleets mainly the 320. This is just a guess but the initial draft to other fleets most likely focused on captains, which may also explain the current skewed ratio on the 777.