As the other partner say, in spanish doesn't exist "la silencia o la silencio" we allways use "el" and the right word is "silencio", it is as a male word. Both ideas are right "El silencio invadía todo" and "El silencio todo lo invadía". The first option is used in common speaks and the second one is more artistic, as if you are reading a book like Hamlet or poetry...

y recuerda que es invadÍa no invadiÁ

"El silencio lo invadía todo" is right or "el silencio invadía todo" but it sounds better the first one, as Marc said.

You can use "lo" in this sentence. And it isn't redundant. "El silencio lo invadia todo." It's like "Ella lo contaba todo". Actually, the sentence sounds better with "lo". Here, "todo" is like an addition to "lo".

we didnt say la silencia. we just say "el silencio todo invadia" and its correct both ways "el silencio invadia todo" and "el silencio todo invadia". you can say it. its correct.