Actually, there are three of them:
Ned, Jack, and Marci.
Where did Mrs. Voorhees move their bodies?
Where were they discovered by the police the next morning?
We know where the others were found, because Mrs. Voorhees did not have time to move them before the pursuit and fight with Alice.
Bill was plastered to a door.
Brenda was thrown through a window into a cabin.
Steve was hanging from a tree.
Annie was tucked away in Mrs. Voorhees’ Jeep.
The only thing we know for sure was that the axe used to kill Marci was removed from her head, presumably by Mrs.Voorhees, and was placed on a bed with the intent of foreshadowing the imminent doom of those who discovered it.
When Alice and Bill went looking for the others, they covered every nook and crany of the camp.
No stone was left unturned, and they checked every cabin with lighting.
If Ned and Jack were left where they were killed, there is no way that Alice and Bill would not have found them in those bunk beds.
And if Marci was left in the shower room, Alice and Bill probably would have found her as well, unless she was behind one of the curtains to a shower stall that Alice did not check.
I suppose the ending of “Friday the 13th” would have been more complete if Alice had discovered all of the bodies during the pursuit before the fight with Mrs. Voorhees.
We can only speculate how the bodies of Ned, Jack, and Marci would have popped up in front of Alice.
Imagine Jack falling off the side of a roof right in front of Alice’s feet with the harpoon arrow still protruding from his neck.
Imagine Ned falling right into Alice’s arms as soon as she opened the pantry door to hide from Mrs. Voorhees, and before she closes the door she sees Marci falling off of a shelf and onto the floor.