Ok let’s talk about dp vs hk as a reversal out of ticks:
Advantages to hk:
-the motion is simpler
-you are in the air longer than a dp, forcing your opponent to use a non-throw counter
-getting hit while doing a hk sometimes allows you to escape the corner, but only if the attacker fails to react and punish you in time
Disadvantages to hk:
-if opponent is doing anything besides walking forward into you, they can hit you basically for free and usually put you back right where you started
-it has much shorter invulnerability than a dp
-hitboxes on hk switch sides making it a shitty attack
-opponent can usually block and throw you for free (though there is debate whether this is 50/50, need someone to do some frame testing here)
It’s fairly obvious that using hk as a reversal out of ticks is almost always a worse choice when compared to counter throw/dp, even if you saw some video of some guy using it and actually winning. Its advantages only outweigh the disadvantages when a certain character (like Chun) doesn’t have a great counter; but even in these fights, it can not be used consistently as a good tactic to get out of ticks. It might be worth it to use it just to mix things up slight in an attempt to confuse your opponent, but a better option is almost always present.
As far as the footsies and fb’s against Hawk, yes you have to be careful when you buffer a fb after a blocked sweep against Hawk, and I would agree that sometimes slow fb’s are better at stopping him from dp’ing through the fb; but you have to mix up fast fb’s as well, or else he will start to jump and dive after blocking a low attack and hit you that way instead. You should usually stick to using only ground attacks or fb’s, rarely buffering them just to mix things up.
Low attack into fb is one of Ryu’s best tools to push a character towards a corner, and cornering an opponent is one of Ryu’s best winning tactics. Having opponents like Hawk and Gief in the corner gives you almost no advantage compared to out in the middle of the screen; being in the corner can give a medicore player the false sense that you will throw more fb’s to keep them there, usually encouraging them to jump or lariat, but discussing non-optimal tactics that are effective against scrubs is probably a bad way to go, so I’ll stop.