● Hayley has met most of the living main characters except Alaric, Bonnie, Enzo and Matt.
● Hayley was Tyler's date to the Miss Mystic Falls Pageant.
● Hayley's The Vampire Diaries' parallel is Tyler.
● Hayley helped Tyler as well as Chris, Kimberley, and probably plenty of other hybrids to break the sire bond to Klaus.
● In the books, Shay is the only female werewolf and female Original Werewolf in all novels. It's a possibility Hayley is based off of her.
● Hayley made a deal with Shane that resulted in the death of 12 unsired hybrids by Klaus in O Come, All Ye Faithful.
● It should be noted that at the end of the episode, Klaus kills Carol Lockwood (via drowning) as further retaliation against Tyler for attempting to get rid of him. Therefore, Hayley is indirectly responsible for Carol's death as she told Klaus of Tyler's plans.
● After she slept with Klaus in Bring It On, it was revealed in The Originals, she became pregnant with their daughter.
● She is the first pregnant character in the TVD and TO series and the first one who becomes a mother during the course of the series.
● Hayley is one of the three main characters of the TVD and TO series to be a parent; the other being the father of her daughter Niklaus Mikaelson and Katherine Pierce, mother of Nadia Petrova. 
● She shares some similarities with Katherine Pierce
● Both came from old supernatural lineage.
● Both are called by an other name that their birth one; Hayley being born as Andréa Labonair and Katherine as Katerina Petrova.
● Both were involved with the Mikaelson brothers.
● Both of their astrological sign are Gemini.
● Both gave birth to a baby girl in hard conditions and their respective child was taken away from them (for Katherine it was her father who took Nadia, while Hayley was killed while the New Orleans Witches took Hope, who she later took back, but sent her to live away from New Orleans with Rebekah).
● Hayley is the first to attempt to kill the baby, by poisoning her. However, she decided not to go through with it. The others include: Agnes, Tyler Lockwood, Mikael, Genevieve, Abigail, Monique Deveraux, and Esther.  
● In Bloodletting, Hayley Marshall's birth name is revealed to be Andrea Labonair. This makes her the second character to go by an alias. The first is Katherine.
● In the case of Katherine however, she willingly changed her real name. Hayley was not aware of her birth name until "Bloodletting".
● Hayley's birthday is June 6th. 
● The Big Uneasy reveals that Hayley has been on her own since 13. Making her the youngest character without parents or guardian.
● In Le Grand Guignol, Hayley, Eve and the cursed werewolves successfully interrogated Céleste on how to break the werewolf curse.
● Hayley is the second member of the Labonair family to have slept with Klaus. The first was Lana in the 1910.
● In Moon Over Bourbon Street, Hayley becomes the Werewolf Representative of in The Faction.
● In An Unblinking Death, Marcel reveals that he saved 'Andrea Labonair' and brought her to Father Kieran rather then use the baby as leverage. According to Marcel she is a tough one like her dad.
● In An Unblinking Death, she reveals that she left her home at 13, after she was kicked out by her adoptive parents.
● In From a Cradle to a Grave, Hayley and Klaus decided to send their daughter away, while the family stay behind to make New Orleans safe for her to live.
● Hayley was reunited with Hope after four months apart.
● Hayley is the eleventh werewolf to be seen killed. She is the first werewolf to be seen by killed by a witch.
● Hayley was the first werewolf seen to die by a slit throat.
● Hayley is the third main character to be a Hybrid.  
● She is the first parent to be turn into a vampire/hybrid by her child.
●The episode, Chasing the Devil’s Tail marks the first time Hayley uses her vampire/hybrid blood to heal a human (Cami).
● She is the first female character to get married on-screen.
● She was cursed in Ashes to Ashes on Klaus' orders by Dahlia only be human on the full moon for a few hours, but this was reverted in You Hung The Moon by Davina Claire. 
● She and Davina were the first, and so far only, ones to use a book reference by calling Klaus and the other Mikaelsons the Old Ones.
● Hayley is the first hybrid to fall under the Crescent curse.
● Hayley is the second hybrid to be created by her daughter's blood, the first being Dwayne.
● Hayley missed her daughter's first steps due to being cursed.
● Hayley was killed in the same manor as Camille O'Connell and Davina Claire (throat slit).
● Hayley is the first main character of The Originals to be widowed.