Thanks for starting this thread, Rashi's daughter! This aspect deserves good exploration.
Yep, yep and yep.....had to plan to remove the body, or else no need for the "fake kidnappers" to leave the note. If the "kidnappers" would have decided or accidentally killed her, either way they would have removed the note.
The initial plan to remove the body was foiled - had to have been. Madelaine, wrapping the body to remove her makes sense, but if it had been planned to put her body in the car and remove it before the rest of the plan could be worked out, could have led to the R's being arrested immediately, IMO.
If an R would have put JB's body wrapped in the blanket, in the car somewhere, fibers - maybe even fuzzies - from the white blanket would have been discovered in the car, unless she would have additionally been wrapped anything that would have prevented the transference, which still would have been iffy.
Fibers or fuzzies from the blanket could have been accounted for if: (this is scenario according to RN descriptions) the money was delivered, and JR was directed to where he could pick-up his daughter, where he would have found her dead and wrapped in her blanket, could have picked her up immediately and placed her in his car for further protection until either police arrived (called from his cell phone) or he sped somewhere else with her to end the event. But, without completing the ransom exchange, if she was gone, which the note indicated she should have been,there would have been no way those blanket fibers would have been in his car.
JB's body could not have seemingly been placed into the car until AFTER the money had been taken for exchange. This would have allowed for an R to have placed her in the car from the house, keeping her there under guise of taking the ransom.
That now leaves two options: to get her her body out of the house by another maneuver, prior to calling in police so she wouldn't be found in the house (which is what the note indicated) under any circumstances, or keep the body hidden until there might be a chance to get it out later.
An attempt to put her in the suitcase, and somehow get the suitcase out of the house, other than by placing it in the car, might have seemed an option. Until it was tried, (there were duvet fibers on her shirt) and discovered the fit wasn't right, or if it was possible to close and latch the suitcase (which was drawn by another poster once), when the attempt to get the suitcase out through the window might have been tried, (allowing the window debris to come into the basement) it was discovered the suitcase was too large, which it was later documented. Then, the only option was to hide her somewhere until the body could be removed later.
This is the first time I have posted my thought about the fracture of JB's skull in connection with the suitcase: I do not doubt the bash produced the oval displacement of skull that was found during autopsy. But I have wondered if the 8" fracture might have occurred when the suitcase lid was closed and latched on her. If her skull was just a bit too large for the suitcase to close easily, and the closing was forced????? Once she was removed from the suitcase, the fracture could have expanded.