If you believe the State's star witness, Jason Autry, Holly was clinging to life when Autry arrived at Shayne Austin's trailer to score morphine and meth on the day Holly was abducted. Everyone thought she was dead, wrapped up in a blanket or tarp in the back of a truck.
The Adams brothers and Shayne asked Jason to help Zach Adams dispose of Holly's body in exchange for wiping away his drug debts/more drugs.
When Autry and Zach Adams backed up to the Tennessee River to "gut" and dump Holly's body into the river, they heard her moaning and realized she was still alive. Zach then shoots Holly, which the noise of the gunshot causes Zach and Jason to abort the plan to dump her in the river. So Holly died the same day as she was abducted, according to the State of Tennessee's drug-addled star-witness.
Jason Autry's complete testimony on the stand in the Holly Bobo case is on youtube. Also, the guys from True Crime Garage have a good 2-part Holly Bobo episode that includes the major points of Autry's testimony.
Lauria Freeman / Ashley Bible, the Oklahoma case where parents were killed and 2 teenagers abducted, may have been kept alive for several days.