i am aware that midi-chlorians are in all living beings, but what is indicated is that a spesific number of midi-chlorians are needed for someone to be trully force sentitive.
what i was talking about and what you was talking about, is that there would not be a spesific number of midi-chlorians needed to be force sensitive, the midi-chlorians allowed one to communicate with the force, its just that the more one have, the stronger that connection is, but even the ones who have a "weaker" connection to the force, are able to use it. Basicly a good reason for why the Jedi and the Sith would only train those who have a strong connection with the force is because for the Jedi, they would train them so that they would not end up harming others if they used their force powers by accident (just imagine a young child force user using force push by accident), while for the Sith, its a no brainer why they would seek out and train the most powerful force users they could find.
but with some people like Finn or Han Solo, their midi-chlorian number would be considert to low to actualy have any force power by both the Jedi and the Sith, but if they actualy trained them, then they could be able to tap into the force like they do, it would however be a bit more difficoult, because they don't have the same amount of midi-chlorians like them. But the idea remains, which would also solve the problem that some people have with the midi-chlorians, namely that no matter how high or low ones midi-chlorians levels are, one is still able to use the force.