Apart from J-31s from China, MIG-35 from Russia is PAF's best bet.
Since MIG-35 is a evolution from MIG-29s, MIG-35s would see the light before J-31 becomes mature.
I would give MIG-35 70% chance against J-31 (30%)
JF-17 & J-10 are single engined and are not comparable to MIG-35s.
If PAF has no problem inducting JF-17s with a Russian engine why would it be a problem for the MIG-35s.
Note that Russia is selling weapons to both China and India. Neither of them have any issues of being sanctioned by Russia.
Yes. As I have mentioned apart from J-31, MIG-35 is the best bet.
Forget about Turkey. It is not going to happen.
MIG-35s could actually be cheaper (cost) than J-31s hence more affordable for Pakistan.