Simulate analogWrite(PIN, 0-255) with digitalWrite

Theoretically, the result is a led with (125, 255, 10) color

No, hopelessly wrong, I'm sorry.

For example this is a crazy thing to do:

analogWrite(latchPin, 125);

You need to go back to basics, design simple circuits and write simple code. You are quite a ways off being ready for your current project.