Knowing that BSG
takes place 150,000 years before our
time, the HMX series are the new cycle by being to modern humanity what the Cylons were to the past humans, hence why they are Ridiculously Human Robots
. Or perhaps they might even be new humanoid Cylon models...
According to the Visual Novel
Marianne knows Aoi Matsubara and Kotone Himekawa from the original To Heart
, Marianne was held back by one year because she wanted to stay with Sasara in school. It was already stated by Word of God
that To Heart 2
takes place three years after the original series. By doing the math, with Marianne having spent four years in the school, that means that she was a first year student when Hiroyuki and Akari met both Aoi and Kotone, who were also first year students.