I agree on what you say here and have added a tool to remove load times (includes a readme on how to add it to livesplit), I've thought better about this and im not sure if the tool is 100% functional so for now im gonna delete it until im sure it works properly.

I agree with doing pacifist and bad ending on the first run as when you beat the final boss it takes you to the main menu, easy to start the second run fast, also you can use the backtrack for the green leaf to fight choir on the second one. To the hard run I would add the no deaths, as doing it on insane will be extremely hard(at least if you arent used to play on insane). Tho as you can unlock insane and then do a run, I dont know whether its preferable to do the hard run then insane or the other way around. For the necklace of sacrifice, you need 700 munny and unless you farm it there isnt enough munny on chests, at least early enough, to make it worth the farm. Basically because on the last three bosses its not that much useful, except choir which im yet to test. I havent seen the run you linked yet, but im trying to do a route of my own having in mind the necesary items, and locations you have to revisit, and the movement necessary/fastest movement/ less backtracking necessary.