If Russia is willing to make sale to a NATO country (turkey) they will sell to anyone point is here can pakistan even afford billions of $'s ...
Turkey is a different case and to explain with regards to Turkey's acquisition of S-400 SAM Systems, it is a bit complicated, I will definitely tell you about it some day.
And now coming to Pakistan getting SU-35 Flankers from Russia, this is very unlikely because 1st of all, Russia is not foolish to sell an advanced jet like SU-35 to Pakistan because this will make "
India" Upset, India is the largest buyer of Russian equipment. Russia doesn't want to lose a market like India for just a few SU-35s to Pakistan.
And lastly, the most important question remains, does PAF have the money to afford a twin Engine Fighter like SU-35?
You should look at Pakistan Airforce's inventory, you will notice one thing which is common, all their planes are single Engine be it F-16, JF-17, F-7PG and now J-10. They don't Operate twin Engine Fighters because they cannot afford the maintenance and cost associated with twin engine Aircrafts.