"If there is a second sensor, my guess is that it is the same as yours, for radar signature collection and location. These aircraft will attempt to buzz SAM defense sites to try to get them to activate"
I based on the yellow spot between the camera windows and the translucent front of that sensor on this JZ8F's belly to think there is at least one more sensor besides the camera.
As for M2000 Vs J8F, on paper, the only advantage the M2000 has is FBW system, but if the jet is used as high altitude, fast interceptor, then with or without FBW means little. From head on, the M2000 may have a smaller RCS compared to J8F, that is why I said it all rest on J8IIF's radar capabilities. Overall, in the days before J10 and J11B, Chinese jets were very very bad for giving the pilots any SA ( situation awareness) information ( Be it electronic or visual) so in a way, M2000 is generations ahead of older J8II in this regard. Let's just hope the newer J8IIF willl correct some of this deficiencies from electronic stand point.
J-8F going against M2000 in close range would be very disadvantageous for the J-8F. The M2000 is a very nimble plane, and the J-8F should take a shot of opportunity then try to bat out of there. Having coordinated 2 on 2 or 2 on 1 tactics is vital as well.
I don't think the visibility of the J-8II from the cockpit is that good either, with the back spine and the pilot having to sit low on a narrow cockpit. It does not appear to have that the plane has a good view of the back and towards the low side.
As for HUD, they were introduced to the PLAAF through the F-7M, and through this, the J-7M (J-7IIB). First as a foreign import from the West, but quickly developed into indigenous design. By the nineties, even J-7E and all the J-8IIs have HUD. Earlier J-8I and J-7s were upgraded to that.
We don't much of the PLAAF SA before J-10, it probably wasn't good, though we expect it to have improved incrementally in the nineties. The AEW and C31 aspects however, are nothing to scoof about because the PLAAF seems to be quite effective in intercepting various interlopers. In 1994, two J-6s buzzed the Kitty Hawk which was trailing a Han class sub, and it was done well out of the loiter range of the J-6s. Apparently somehow, the sub managed to communicate coordinates to the J-6s which didn't even loiter to search.
I suspect before the "modern" PLAAF, the PLAAF heavily relies on the GCI, or ground control based interception. What they lack in terms of onboard SA, they make it up, classic Soviet style, through a network of ground based sensors passing data and instructions to the fighters. However the Soviet system is based on intercept, and treats the pilot basically as a nonautonomous drone. The pilot simply follows orders, and the basic mission routine is to take off, follow the instructions to the target, fire missile, come back home. Anything else is superflous. Of course the brainwork is being done on the ground, kind of like a person playing an RTS game, where the ground controllers have the overall picture, and are using strategies to concentrate forces, ambush the enemy missions, then run away, like an airborne guerilla battle. When your pilots is not as well trained as the opponents, its not a good idea to hang out and go toe to toe, despite the MiGs being maneuverable and all. The MiGs also have limited fuel, so it was better to go home than attempt to dogfight with limited fuel resources.
The J-8s were probably concieved along that principle, along the same lines of the similar Su-15 Flagon.
BAck in Vietnam, this system of interception actually works very well so long no one touched the GCI network. The Americans didn't want to risk Russian and Chinese adviser casualties and risk escalation of war. But if the GCI network is attacked, it can be very disastrous to those who use it.
I think for the Russians, this began to change with the MiG-29 and Su-27. Design of planes do reflect doctrine, and by improving the onboard sensors of the aircraft, they have shifted autonomy from ground to pilot. Although it is too late when the Soviet Union ended.
I think PLAAF began its change not when they got the J-10, but when they first have the Su-27s. At one point, PLAAF pilots didn't even thrust their radar, because their radars were unreliable or give false readings. They were highly reliant on GCI instructions and not used to deciding autonomously. But training with the Su-27 began to change that gradually. A lot of changes also occur by studying Western examples, when the PLAAF, like much of the PLA, suffered culture shock in the early nineties how much they have fallen behind.
Going back to the J-8F, I think all the onboard sensor improvements would improve its standing in modern combat, kind like an upgraded F-4. GCI interception and control is still a valid doctrine, though now we have merely modernized the concept with AWACS, electronic scanning radars, and modern datalinks, with a lot more sensor information sharing.