only skimmed your post so not sure if helpful but I wrote this a while ago. https://forum.effectivealtruism.org/posts/zLi3MbMCTtCv9ttyz/formalizing-extinction-risk-reduction-vs-longtermism
Also you might find this helpful
https://forum.effectivealtruism.org/posts/zuQeTaqrjveSiSMYo/a-proposed-hierarchy-of-longtermist-concepts
only skimmed your post so not sure if helpful but I wrote this a while ago. https://forum.effectivealtruism.org/posts/zLi3MbMCTtCv9ttyz/formalizing-extinction-risk-reduction-vs-longtermism
Also you might find this helpful
https://forum.effectivealtruism.org/posts/zuQeTaqrjveSiSMYo/a-proposed-hierarchy-of-longtermist-concepts