It's an interesting list your students have created. I've read at least pieces of each of those series and understand the attraction of them all. But very little of this list are titles that I would guess will stay with the readers throughout life.
The one most likely to, IMHO, is Harry Potter. My experience of it, and that of my children and customers, was that the year or more between each book was crucial to one's appreciation of the series. A new book would come out, it would be inhaled by all within a week of publication, then it could be savored. There were re-readings, and intense speculation about what would happen next. The characters soaked into kids' consciousness, so that when the next book arrived, one would be reacquainting oneself with old friends. Rowling's little asides and character tics were appreciated all the more for the familiarity. I often wonder how the easy availability of all seven books affects readers' experiences now. I suspect your current freshmen had most of them available when they started the series.
The Percy Jackson series by Rick Riordan (first syllable pronounced like "fire") has been phenomenally popular. The basic concept of the books, starting with The Lightning Thief, is that there's a group of kids in contemporary society who are the half-mortal children of Greek gods and goddesses. Riordan, who used to be a middle school teacher, says he invented the stories to interest his own children in Greek mythology. The popularity of the books has created a wave of interest in anything related to mythology -- it's been fascinating. Two years ago, Riordan spoke at the Washington DC Book Festival on the National Mall. The tent where he spoke was overflowing with kids clutching their books. When he arrived on stage, it felt like a major rock star was there: the crowd cheered, screamed, waved, jumped up and down. Riordan has started two other series: one on Egyptian mythology (biracial brother and sister, separated by divorce, who are direct descendants of Egyptian gods), and a follow-up to Percy Jackson, introducing Roman mythology.
I will confess to you something I don't often say aloud. When I first read The Lightning Thief before it came out, I stopped after two chapters. I think the deciding moment was the scene where a teacher on a field trip turns into some sort of monster with knives shooting out of her fingers. It's a very action-action series, with teenagers constantly deciding the future through individual combat. Parts have more depth to them too, but I wonder about the series' staying power. What do your students talk about liking about Percy Jackson?
I think of the Sisters Grimm as being a bit younger than the others on your list. Also very popular, in part I think because it maintains good mysteries through the books. The sisters have inherited the responsibility to keep fairy tale characters confined to a small town in upstate New York and not let them escape and wreak havoc on modern society. The characters, with well-known names from fairy tales, all have personalities fairly far off from how they are in the original tales (Grimm and others).
I'm surprised and pleased that The Agency, by Y.S. Lee made it onto the lists. It feels a step up in both sophistication and language. You've already linked to an enthusiastic review. The fact that the heroine is Anglo-Asian, and that the author has a PhD in Victorian literature and culture, give the books a deeper, engaging edge. The heroine is fallible in sympathetic but sometimes excruciating ways. Your parallel to the Sally Lockhart stories is a good one.
I'm curious to know more about why your students love the books they do. Anybody out there who wants to talk about your favorites?
Or maybe I'll just hear more from you...