According to this answer Rav Hai Gaon and Shmuel Hanagid were of the opinon that when it comes to aggadah one should take from such passages whatever comes to one's mind, so all of this is my own speculation.
hair's function mirrors that of clothing for many animals. Though its uses are limited and mostly vestigial in humans, it still mirrors clothing in an aesthetic way. Also hair, specifically on the body is obviously hidden for the most part by clothing. Finally, clothing in general is meant to cover up our naked bodies, and the instincts that are roused by them.
Concerning Judah
Figuratively, hair or 'nature's clothing' if you will, represents a person's inner natural self, which is why 'hair of the heart' is specifically mentioned. Hair specifically was chosen because it has an unnatural counterpart that covers it, by way of clothing, (see above).
Rabbi Hanin in the first passage is saying that, Judah's anger, unleashing his inner self, was frighteningly trans-formative, tearing through his general demeanor, which was presumably much more refined and polite. This is certainly an astute observation about anger in general, as well.
The Sages of Beit Shiloh, who are quoted in the second passage, accent the magnitude of Judah's wrath, and the power of his anger, and of anger in general.
They mention five layers of clothing, and only one hair. The five layers represent Judah's extensive but imperfect self-control, mirroring the number of words in the penultimate benediction of the Priestly Blessing, which invokes more focused divine favor than the first benediction, but does not yet bestow the peace of the third, seven-word benediction, which can remove the final 'hair' on a person's heart, providing them with absolute inner peace and breaking anger's hold on them. The single hair of instinct on Judah's heart tore through all of his mitigating discipline.
Concerning Samson
Samson was not a man of particular prowess, naturally, he is in fact said to be remarkable un -fit for the many acts of strength he performed, being lame in both of his legs, per Rav Asi in Sotah. Rav Asi probably means that in all worldly achievement, (accomplished by physical action, such as walking), Samson was hindered.
Rabbi Nahman is emphasizing when Samson gained this strength, his hair and what it represented was the cause of this prodigious change.
Samson's hair was what made him fit to receive supernatural strength, by way of divine bestowal. It was a core tenant of his nazirite oath to disregard the physical, and the only overt testament to that oath on his person, (as opposed to drinking wine, which is a mannerism, not a feature). Thus it was said to stand on end a lightning rod for miraculous feats, whose renown traveled throughout his tribe's territories, from Zorah to Eshtaol.
His hair crashed together, sounding like a bell, as the bells on the high priest's overcoat would sound as he walked to perform service in the temple, (verses 33-34). Just as the bells served as a constant reminder of the High Priests lofty services, and the reverence they demanded, so did Samson's hair. It reminded reminding him that, even though he was to infiltrate the Philistines under licentious pretenses, developing relationships with many Philistine women, he was always to remember his purpose for doing so. Only that would protect him from harm, (and his hair did, until he parted with it).
