There is no way that the coroner could ascertain the make and model of the firearm that created the bullet wound. The Winchester model 70, the alleged murder weapon, was made in a few calibers, from .223 to .458. Additionally, another brand of firearm in the same caliber could been used.
As Lassiter was telling Ruby and her friends what he believed happened to Stu, you can see Jessica smiling in the reaction shot, trying not to laugh. However, she isn't actually smiling. She's trying to hold it together and not burst out crying, which contorts her face. In the next shot, of course, she can no longer control herself and ends up crying anyway.
The newspaper article supposedly detailing Stu and Brian's bankruptcy actually consists of three paragraphs that keep repeating and have nothing to do with the title.
Derek and Ruby are surprised by Gus and Shawn when Derek is about to push Ruby off the cliff. Shawn and Gus were on a motorcycle, so they would have heard them approaching long before they arrived.
When Shawn asks Gus what happened to Derek during the paragliding descent, Gus says that he clung so hard that Derek passed out and that his helmet also hit Derek in the chin. Gus was behind Derek so he wouldn't have been able to hit his chin;