Yes, radar integration is essential. I am not an engineer but I think technically it may be possible to have radar and links to be separate but I do not yet know if there exist such a solution, I may be mistaken. ARH missiles use a shielded rear pointing antenna while aircraft have a number of hardware based high power directional links to send commands which are deeply integrated with/in radar. I think the main issue is always to make guidance jam and spoofing proof etc..
The most important question is, will Chinese be ready to share finer details of an AAM which a significant portion of their fleet rely on with a western manufacturer. Or will this give serious heartburns to some in Beijing even if such info gets shared accidentally. On the other hand, if Chinese are not ready to share kinematics data or radio link protocols, will a western manufacturer be ready to allow Chinese to get near their radar systems to provide requisite integration.
Also, All AESAs are not born equal and are greatly dependant on the technology of their TRMs as well as choices of TRM antennas and their density for the amount of gain they can provide. Most older AESAs as well as new russian Zhuk one carry a flat panel antenna mimicking the older slotted array in terms of gain. F-35, Elta series and to some degree Rafale's is touted to have TRM antennas to provide best density and gain. What antenna types and density Chinese AESAs carry, I have absolutely no idea..
Although when it come to the world of procurement, with so much money at stack as well as pre-existing prejudices, anything is possible but for a pointer to possible choice of a radar I'll point you to a couple of promotional videos PAF released earlier. In one of those an officer says that we presently have TWO on TWO but will prefer to have FOUR on FOUR...
On IRST..
Most pilots are basically operators.. but to manufacture a platform and to keep it going further PAF had to learn sort of 'grand parenting' a platform solution. I had opined earlier that FLIR currently is more important than IRST, that was before info on turkish pod was released to the press.
With IRST you can do detection, with a coupled FLIR cum laser solution you can produce a fire control solution provided you have an appropriate missile for this as well which does have required 'extended range'. Currently Rafale is capable of this with MICA. F-35 do look to have incorporated this hardware above nose but AIM-9X ext3 was put on freeze, so no idea what it will be coupled with.
I think that provided PAF gets its way it will try to take more of a IRST cum FLIR route rather than pure IRST route..