Based on my understanding, the present is the REAL WORLD.
The book or novel is their FIRST LIFE. And the memory that Huimin has and believed to be real is actually a FAKE WORLD built from Huimin's drawing. Hope that helps,, my English sucks.
No. The present is the book, the omegaverse. Thats why he said "I dragged you back to Silence, which is a book — which he also confirmed. The non omegaverse world is the fake world.
If thats not a book but a the real world (w/ omegaverse) then they should've narrated it differently. They could've said that "Silence" was their past life written in a book that just happened to pop up in the fake world. A record of their past life. However Iheon Cha said something similar to "were a fiction written for entertainment" he also kept mentioning they were from a book. That their life was pre written. So who wrote the book silence? No one. In the end they were both just a fiction only existing in "Silence"
Its a bit confusing because he said they were from a book and that this world is built by Huimin, by his drawings. THEN WHERE IS THE REAL WORLD?? Did he break the 4th wall or something