Cain also crushed Gallagher's best high school 1500m time by 5.6 seconds and there are only four other high schoolers ever within 6 seconds of her time, while Wilson's still almost a second off of Gallagher at 8 (just over 2 s ahead of the sophomore Cain) and at least 12 runners are under 3 seconds off of her time (or better: Gallagher).
These lists are not much updated but I added a couple of times in that I knew of.
800 METERS
2:00.07 Kim Gallagher 1982
2:00.91 Ajee Wilson 2012<<<<
2:00.9x? Chanelle Price (2010?)
2:01.7+i Mary Decker (as a sophomore) 1974
2:02.40 Robin Campbell (as a freshman) 1974
2:02.9 Kathy Weston 1975
2:03.02 Leann Warren 1979
2:03.03 Wendy Koenig 1973
2:03.34 Mary Cain 2012<<<<
2:03.54 Joetta Clark (as a junior) 1979
2:03.73 Rebekah Noble 2005
2:03.7 Diana Richburg 1982
2:03.8 Charlette Cooke 1966
1500 METERS
4:11.01 Mary Cain (after her sophomore year) 2012
4:14.x Jordan Hasay 2009?
4:16.6 Kim Gallagher 1982<<<<<
4:16.8 *Francie Larrieu 1969
4:16.8 Polly Plumer 1982
4:17.61 Sarah Bowman 2005
4:17.84 Alisa Harvey 1983
4:18.06 Lynn Jennings (as a junior) 1977
4:18.62 Suzy Favor 1986
4:18.6 Margaret Groos 1977
4:18.8 Arianna Lambie 2003
4:18.9 Kathy Gibbons 1972