Hi lucas.cambon, you said “… Sotāpanna occurs upon attainment of the seventh stage. The right path (#6) is the gradual understanding that all formations are impermanent, suffering, and non-self.”.
Did you mean “… understanding that all formations are anicca, dukkha, and anatta“?
Because:
anicca is not “impermanent”
dukkha is not merely just “suffering”
anatta is definitely not “non-self”
About the reason behind this conclusion, please refer back to posts (Anicca, Dukkha, Anatta) on this (PureDhamma.net) site. Both logical evidences and based-on-the-suttas evidences.
About your details steps to Sotapanna, I don’t have any comment because I think everyone has different approach, but we need to get the key concepts right from the get go.
On the way to Stream Entry.