If we're talking in the body of the post now, I think it would make sense for cephalo kids to have mammal phases. I think it would be common for younger inkfish to get human and dino history/timelines mixed up, the same way a lot of humans mix up prehistory. I also think they would often confuse the pre-surface life era with the post-mammalian era, since to them both timeframes would be before life moved to the surface. There would be inkfish kids getting a bad grade on a test because they wrote that humans came out of the water before the dinosaurs did.
It's also possible that instead of viewing us like we view dinos, they could view us like we view ancient civilizations. I think this is less likely, since it doesn't seem like it's public historical knowledge that they came partially from us. Still, the fact that we left so much behind lends credit to the possibility of humans being seen as an archeological mystery instead of a paleontological one. This would only apply to humans, though, since other mammals didn't leave as much behind. This leads me to my third theory, which is that they would see us like we see cavepeople, and non-human mammals would be ancient animals to them the way sabertooth tigers, wooly mammoths, and direwolves are to us. Meaning their equivalent of the Ice Age movie would be about our modern animals.