Versus Gen :
I don’t have a good strategy.
What i know is he have a stance to beat long range poke of chun li and his other stance is for close range offense.
Knowing to recognize them will help you a lot for guess his next actions.
In my opinion the stance for poke gameplay à la Chun Li is the stance where he has his 2 hand in front of him (Mantis). When he is crouch he have also his 2 hand front of him.
Why ?
Because in this stance he has a good cr mp, cr hp, cr hk. Don’t try to mess with this at far range 
He has also a good far lp, far mp, far, far lk and far HK. Specially the far HK !!
If he jump with this stance it’s for reach someone at far range also.
Now in my opinion his other stance (Crane) is for close range if you look his normals and jump.
About his specials move, his moves when he jump on the wall have a “long” recovery at the end.
If he whiff those move in front of you and you have your ultra 1 charged you should be able to punish him.
Any variations of of this move have at least 12 frames of recovery on the ground. Even if he do no kick
When he just cancel by nothing he has 16 frames of recovery on the ground.
He has also 4 way to jump on this wall ( LK, MK, HK and EX)
LK made him hit the wall at the lower height and HK is the hight height.
This has an impact on his choice.
Go in training mode to see how limited his choice are depend on your situations on the stage. Like that you will be ready to prepare a good punish and why not your ultra 1 ^^.
Oga (wall jump) follow by the far kick (when he travel the stage like adon jaguar tooth) is not safe on block. According to the frame data it’s -13 if he hit you with the first active frame.
Now (if i not wrong) if he hit you with the last active frame Gen is at… -7 on block
so a reversal ultra 1 can deal with it.
Be careful, the blockstun of this move is very short so you will have to do your move really early to do a reversal
About his hundred hands, be aware that this move has a really fast startup and is safe on block most of the time. So don’t be surprise than a Gen use this move during your pressing. The HP version has 3 frame startup !!!
My advice his during your blockstring, if you let a blank, manage to use a low move at this moment.
Because a low move (cr mk) will beat any hundred hands since you will hit him low. It’s the vulnerability of this move at the beginning.
This advice works also in mirror match versus mashed ex legs.
About his DP and how to punish. I think you should just punish him while he is in the air with a close hk.
I know it’s look like a weak punish but it’s 100 damage and 200 stun and a reset situation for mixup.
On his wake up, his dp is not a good option (except the Ex version)
Why ?
LK version have 3 frame invincible, yes, but the move hit at the frame 5.
What that means ?
At the frame 4, he lose invulnerabilty before he can actually hit you.
MK version have 4 frame invincible but the move hit at the frame 7
So at the frame 5 and frame 6, Gen is FREE
Idem with the HK version.
The thing is to time your attack to have active frame when he lose invinciblity.
Going for a meaty is not an option. You have to delay your attack and use a move with a lot of active frame if possible
Training mode will help you. It’s not something that you can improvise during a match !!
Other thing about his DP !!
Only the LK and EX version will hit you if you are crouch.
MK and HK will just completely whiff versus any crouch move on wake up.
So my advice is : Work on a simple setup with cr lk option select sweep.
Time you cr lk to beat a reversal Gekiro lk (no meaty).
If he backdash you punish him.
If he use another version, he miss you
If he use Ex version you lose
PS : On his wake up, don’t forget his super. He can use them and because both of them are really fast don’t be too confident.