@Deino
As you said 'J31"does not exists.
this begs the question why PAF is harping about 5th generation aircraft which it calls J31?
My point is simple, PAF has never i mean never purchased/Inducted an aircraft who does not have a supply chain or 10 years of service history with OEM. Its not a joint venture so any idea like JF17 should come in mind (for that its PFX) so to be honest my opinion is if the 5th gen is to be inducted and only one with proper researched flight envelope and deployment tactics well established in J-20A with local engine (WS15) either PLA now has decided to export J-20A be a export oriented version.
We and others at PDF also think its outlandish that J31 which actually does not exists is been touted by PAF high ranking officers on live TV specifically mentioning PFX and J31 as two separated projects.
Rumor mill is running wild off course! and this is just the way it is. "Soon" can not mean 10-12 years not even 5 years soon means 1-2 years other then J20A it is no other that fit the mold!
so i if china decided to export 5th gen why you are so sure that its J31/J35 or whatever, it should be J-20A (policy shift)
think about it for once