During the opening flashback, Troy's body changes positions against the tree in alternating camera angles.
While Dr. Loman removes Rocco Damara's pants, he sees that the zipper is undone and he starts a conversation about the original case with Walter. By the end of the conversation all the victim's clothes are in plastic bags. However, nothing in Dr. Loman's posture indicated that he continued removing and bagging the clothes while talking to Walter.
The stab wounds from a knife and a javelin head would be VERY different. Knife wounds would be narrow and slender, a javelin wound would be round. The difference in wounds would be obvious. There is no way such wounds could be confused with each other.
Javelin is not allowed in high school in Florida. There are a few states that allow in (14 in 2017), but Florida is not one of them.
When arresting the victim's father (Bruce) in a bar, there are multiple glasses of beer, spread around the bar and tables, yet Bruce is the only patron in the bar.