Back Kenpo:
iFF2 and F4 are Jin's main options for hitting Back Kenpo reliably out of poke situations. Even his DB4 can often whiff on it. 4 hits it only at range 0.
To give a rough idea, from a blocked range 0 Feng DF1, Jin's 1, 4, D4, DF1, UF2 and F3 are evaded. 1-2 is blocked, 2-1 clips with the second hit, a well timed dash EWHF hits, DB4 hits. At any further range than this, DB4 and 2-1 whiff and can be punished, and dash EWHF may be impossible to get better than a forceblock on. Pretty much only F4, FF2, UF3 and iCDS3 will hit at this range.
High evasion:
Feng DB1 evades jabs fine but not EWHF. It also only evades Jin 4 past range 0. However, this means after a hit Jin DB4 or most other blocked Jin moves (bar 123), it will evade 4. This can close off many of Jin's homing & tracking tools, as they're too high or too slow. Note that Jin's F4 trades favourably with DB1; he can still get the wavedash D2 afterwards. Be wary of getting DB1-2 parried and launched, as well.
If Jin has the execution, he can also counterhit DB1 with a (non bufferable) EWHF out of blockstun, or use iFF2 from + frames.
Feng 2-tilde-1 tends to evade Jin's 1 and 2. If he begins dashing in to counter Back Kenpo, you can try to confirm a massive launch on him with this. Jin can launch the second hit of this if it's delayed, using his parry. If undelayed it's a force block.
Other:
Jin is less vulnerable to Feng F4-4 than most Mishimas, as he can whiff punish F4 with his own F4 and get a guaranteed F4>ZEN>ZEN1-2 if it hits you backturned.
Jin's i14 WS2 can launch Feng's QCF1 on block. The midpoint of QCF1 evades F4, FF2, WS3, CDS3, and crushes EWHF. As with any Mishima, Feng's command dash is helpful to move in without the threat of EWHF. Remember that Jin's EWHF did not receive the EWGF recovery buffs.
Punch Sabaki:
Not particularly useful in this matchup. Can parry the safe final hit of BF2-1-2, or the mid in CDS1-2.
UF2:
4 makes this scarier to use, but 4 is also scary for Jin to use and UF2 still evades or CHs just about everything else. Noteworthy is that this gets an aligned CH if he tries to sweep/FF3 50/50 you.
Jin Parry:
B4 is -14 if parried but DF1 is only -5. 2-tilde-1 second hit and DB1-2 second hit are launchable on parry, as is the third hit of WS1-2-1. Headspring is launchable on parry but he doesn't appear able to do this on oki, which is where Feng typically uses it. DF4-1+2 also cannot be parried and is a force block.