Is the Avery who is Snape's friend a relative of Avery who is in Tom Riddle's circle?

Question

In Harry Potter and the Half Blood Prince when Harry and Dumbledore are in Slughorn's memory they see see Tom Riddle with a bunch of other students in Slughorn's office. Among them are Lestrange and Avery:

'Good gracious, is it that time already? You'd better get going, boys, or we'll all be in trouble. Lestrange, I want your essay by tomorrow or it's detention. Same goes for you, Avery.'

_{^{Harry Potter and the Half Blood Prince Pg 463}}

In Harry Potter and the Deathly Hallows when Harry is in Snape's Memory he sees a conversation between Lily and Snape where Lily mentions an Avery:

'...thought we were supposed to be friends?' Snape was saying. 'Best friends?'

'We are, Sev, but I don't like some of the people you're hanging around with! I'm sorry, but I detest Avery and Mulciber!...'

_{^{Harry Potter and the Deathly Hallows Pg 540}}

Tom Riddle and Severus Snape are not in Hogwarts at the same time so my guess is that the second Avery is a son or some relative of the first. Is that right?

Answer 1

They’re likely of the pure-blood Avery tree.

Both wizards named Avery and affiliated with the Dark Lord are almost certainly members of the pure-blood Avery family, one of the twenty-eight truly pure-blood families.

In the early 1930s, a ‘Pure-Blood Directory’ was published anonymously in Britain, which listed the twenty-eight truly pure-blood families, as judged by the unknown authority who had written the book***, with ‘the aim of helping such families maintain the purity of their bloodlines’. The so-called ‘Sacred Twenty-Eight’ comprised the families of:

Abbott
Avery
Black
_{^{- Pure-Blood (Wizarding World Online)}}

Pure-bloods are one of the groups most likely to join or support the Death Eaters, as the Dark Lord wanted to put pure-bloods in charge, and several of the surnames in the Sacred Twenty-Eight are also found among the ranks of the Death Eaters.

“Were – were your parents Death Eaters as well?’ ‘No, no, but believe me, they thought Voldemort had the right idea, they were all for the purification of the wizarding race, getting rid of Muggle-borns and having pure-bloods in charge.”
_{^{- Harry Potter and the Order of the Phoenix, Chapter 6 (The Noble and Most Ancient House of Black)}}

Therefore, they’re almost certainly related by being members of the same pure-blood family, though exactly how they are related is not mentioned.