I believe Lucas bad idea for Midichlorians came to him when he was reading a scientific study on mitochondria.

Also in Episode III Qui Gon was supposed to explain more about the force how you could join it with your physical self, something about the whills or something. Then he trains yoda and then yoda trains obi wan.

This is how they exist in the force to defeat the dark side, whilst those who die as sith perish and there souls are not preserved. Plus they can teach Luke as voices of wisdom.

This is canon the EU had dark jedi and sith surviving but that is EU nonsense. Like the Dark Empire emperor, Freedon Nadd, exar kun.

Or at least it was canon until Liam Neeson refused to Reprise the Role of Qui Gon Jinn. But it is still in Matthew Stovers novelization and the shooting script.

As for Yoda Struggling to lift something in episode II that was done for weight and scale, to make it seem more real since cgi is incredibly fake.

In earlier Drafts of Revenge of the Sith you find out that the emperor influenced the midichlorians to create Anakin, so he is he father in a way. Making him Darths Daddy and Lukes Grandfather,lol.

Supposedly this was the Thing He learned from Darth Plaguis the wise.

I think in the same early revenge of the sith plots though Han Solo was raised on Kashyyyk and was Chewies Brother though adopted. LOL terible ideas. And you think what made it into the final cut is cringe worthy.