I'm not convinced that Maya was killed by the device, that's easily the biggest hole in this theory and requires a much larger leap than having the stranger be Maya. She obviously left the notes behind on purpose, they weren't just found, so you are making the assumption that she went on a suicide mission into the device instead of leaving the facility like she explicitly says she plans to do: [quote] I’m resigning... I can’t take this journal out with me, so I’ve left it for the others, and asked them to continue the log.[/quote] We already know that Maya experimented with/built time travel devices and would therefore be as knowledgeable as anyone (and hardly timid about doing so). No such evidence exists about Chioma doing that kind of independent research, though admittedly I don't know what was going on at Hyperion. Maya's questioning about the implications of time travel are also cited in the hunter cloak "The Ishtar Dilemma"(small aside, while not a guardian, the Stranger certainly has a hunter character model.), further cementing a picture of the type of person who would make herself into The Stranger to, in her own words, [quote]"....bring something back to now. Something you needed." "Or go forward and learn something vital. If you knew how to control it, how to navigate across space and time"[/quote]