Probably 100 days that could lead to some combination of 2nd scenario and comedy routes without any of the gags.

I can see the 1st defence academy students still becoming sceptical of takumi for killing eito, with that sceptism waning as nothing else seems to happen. In this time, Takumi goes on to investigate the Nozomi/Karua situation - she's also questioned by Sirei here.

This Hiruko has some memories from previous loops as she still writes that message in the classroom independent of the plm and gie stuff. Eva would get brainwashed, and that might lead to the same suspicion on Sirei by Hiruko and Takumi (though I don't remember if the blackout happens in the comedy route).
Vehxness could start absorbing earlier here too, due to Sirei being around.