Don't you think it is a bit arrogant? The J-31 if it ever materialises is the best option Pakistan will have and you portray it as if it is "useless"?
The fact that the PLAAF is not (as it seems) procuring this type is indeed compelling but has an easy explanation, they have different assets and why going for a smaller, less capable fighter for the PLAAF if more J-20 and later J-20A are the better option? The J-35 is a naval type... and again, for Pakistan the best it could get since the J-20 is not for sale and Kaan IMO more a huge questionmark on almost everything as long it has no indigenous engines to replace the too weak F110 engines.