You can't just strip out vital systems without putting in replacements.
Given the timescale and number of units concerned, I am pretty doubtful they would have developed bespoke export versions of key systems and integrated them. Especially since these 3 are supposed to be a gift, so there won't have been foreign development funds to pay for all that work.
As Pakistan start to test and use them, they no doubt would form their own lists of modifications they would want made to best suit the local conditions and what they want the helos to do.
That is not the common procedure for countries that want exports. Usually they use downgraded parts of their own with a different software component like in case of Arbalet radar for Iraq, which operates only in MMW while the russian one is mutlibandwidth with L-band for air targets. The Iraq Arbalet can only track ground targets, ground mapping and NoE automatic flight support along with terrain avoidance, but no 360° air track mode. The same comes with targeting system, they did not install all the goodies like for domestic version like image processing.
The point is, the common approach is to give them a downgraded version good enough for them but without comprimising own capabilities and look later what the customer wants to change.
In terms of security, I think attack helicopters are kinda in a unique category.
Unlike with sensitive systems like fighters, SAMs or subs Etc, an enemy won't really be in much of a better position to be able to counter and defeat attack helicopters if they had details about their key systems.
I think that is one of the key reasons the PLA allowed this gift.
Actually they have systems, usually defensive systems that can be evaluated and analyzed to develop algorythms to filter decoy sequences out which are stored on databanks of AH computers. They have different sequences of flaring for identified threats which optimizes the interception rate, if they know those sequences they can and already have in the past with 2nd gen MANPADS and ATAM's developed filtering algorythms and todays 3rd gen multispectral matrix working seekers are kept therefore constantly with new databanks of IR fingerprints of aircrafts and that is kept secret with their filtering and algorythms, same goes for IRCM, DIRCM and flare sequences which would comprimize either the effectivness of MANPADS or the effectiveness of protection suites.
There is no indication Z-10 will ever use WZ-16. I would think this is model looks more or less what PLAAF uses.
Actually there is and the mentioning that the development of WZ-16 which is based with work of Turbomeca on helicopter engine for 6-8t class helicopter that is suppossed to go for exactly this kind of weight class, not to mention they can not stay with WZ-9 since it has pathetic shp/t ratio right now, which limits its payload and flight caracteristics. If the Z-10 was suppossed to work with WZ-9 engines they would already have finished the work on IR Suppressors, but they did not, because IR suppressors are specified for engine exhaust and pressure, not to cut the engine to short and lower their shp and not to develop with valueble resources IR suppressors for WZ-9 engines when it is about to get a necessary upgrade.