So, just to clarify how the loop works
Takumi in route 0 goes back in time, replaces his consciousness. He makes decisions until day 100 or he dies, then he's sent back to day 2. Then that timeline exists at the same time as a new timeline that's being created from his different decisions. Then when day 100 rolls around, both Takumi's are sent back to day 2 as one guy until the branching starts?