I don't think we are going to agree on this and that's ok. In taking your bolded statements above specifically, Magneto is only 8-10 years older than Xavier and Moira. So when Charles and Moira are in grad school is likely the time frame that Anya dies. As a few "years" later Charles and Erik meet in Israel after the Korean War. None of Erik's kids are mature as one is dead and the twins are toddlers likely.
Truth is that regardless of who we are discussing, the timeline is fixed in that events happened in sequence of canon. So taking anyone's age into account is problematic as characters like Emma, Xavier, and Magneto have been de-aged (either in story or through editorial means) which puts a kink into timeline theories based on ages. But the sequence of events that happened in the comics still happened in that order. Yes, I 100% agree Emma is supposed to be an older woman, but that got changed by Marvel years ago so we cannot use previous artwork to define her age as it is stated now that she's only in her late twenties. So taking out everyone's age and the idea that it follows our linear calendar in the real world, we are given the idea that things have been happening for 20 years. So within 20 years all of our X-lore has happened, in the order it was presented. Because if it isn't in that order, then it is not 616 as it no longer follows canon. So going back to the discussion of Exodus - he was not discovered by Magneto until after the events of X-Men 1-3. Which chronologically happened right before the events where Emma was attacked by Fitzroy in Uncanny X-Men 281. Where Emma was clearly an adult, not a child.