Harry Chapin once said he had three heroes: Pete Seeger, Ralph Nader, and the late Congressman Allard Lowenstein.
One of the three is name-checked in this chapter: Ava's husband Raphael (the closest 1868-era equivalent I could find to "Ralph".)
Two other people are also referenced. Harry Chapin was a bit unique among folk-rock singers of the 1970s in that his band included a cello, and he had a string of them over the course of his career. The name “Ava Cavill” is a reworking of the name “Yvonne Cable,” the last of several cellists who toured with Harry. If it is possible for a third-grader to have a legitimate crush, I had a crush on her. To her successor in Steve’s band, Arlen Hlusko: you are both beautiful and uber-talented, but I would sell my firstborn child for the opportunity to enjoy Yvonne’s musicianship again... and to see her sing “Circle” live, since Harry had the poor grace to end her singing career by leaving us only a few weeks before my mom and I would have “gotten together again” with him and the band.
Also, Tim Scott (namesake of the porter who carried Ava’s bags on the day she and Annie met) was his first cellist.
Finally, there are the two side characters: Dr. Daniel Tyson and William Wheedon.
School shootings didn't just appear from whole cloth in the 1990s, although they used to be far less common. One of them happened on August 1, 1966, at the University of Texas. Harry wrote about it for his 1972 song, "Sniper." Bill Wheedon and Danny Tyson are two of the (fictionally-named) victims in the song.
Trigger warning before you click on this link: the song *still* scares the hell out of me when I listen to it.
Addendum: in looking for an image of Yvonne Cable that I could link to, I found this tribute to her following her passing in 2023.