1. Yes, the plane was crashed on purpose. It was a billowy, Universal Studios-style crash, almost directly upwind. The pilot lied about many things.
2. The NTSB has a nice, long irrelevant report concerning the tear-down of an engine that was not on the Cessna Grand Caravan when it crashed. That report shows compressor fan blade fractures that impacted the shroud and took out large portions of all the rest of the fan blades in both the hot and cool sections.
It was the correct engine logged to have been on the craft, but that engine was replaced, almost certainly the previous day, when that craft was said to have been in the commuter airline owner's repair shop. I believe the logged engine was sabotaged to manifest the compressor fan blade failure that Pratt & Whitney Canada (P&WC) would later find. The pilot's movements in the video show he used manipulations of the controls, specifically, POH-prohibited use of the Emergency Power Lever, that would likely cause the type of failure P&WC would later find. With all the other lies the pilot brought forth, I believe it likely that he was the one to have sabotaged it in the shop--just as he tried to recreate in the air. The video's audio track, vis-a-vis the engine and cabin sounds were certainly edited, though it's not clear by whom.
3. Small numbers of people in the FAA and NTSB were necessarily "in on it." The NTSB Investigator in Charge allowed the report to declare that the engine and airframe were found already separated on the ocean floor, when all the visible mounts, struts, cables, etc. show obvious saw cuts were the cause of the separations. There were clearly multiple cuts on all visible members, which suggests that there were indeed two engines, an admittedly surprising fact that was confirmed by much other evidence. Any responsible investigative team member that implicitly or explicitly signed off on that set of facts was corrupted., or would have to be considered incompetent, which no one should believe.
4. She was not killed, nor did she die. This was the CIA-asset's exit to Valhalla. She was a loose end. They would not want her subjected to questioning, from a court or Congress. She was responsible for having procured a false document to cover-up Barry's usurpation of the presidency.
A new life, a make-over, pension, and money for her ostensible "family" to come from the main competitor to Barry's Chairman of Jobs and Opportunity council, a foreign company, was, I'm sure, OK with Team Barry.
This evidence should speak for itself on what lay before the Medical Examiner (ME). There is lots of confirming evidence, but hopefully this will suffice for now. If you want it all, there's a book.
5. I imagine you're saying that if one is coerced or threatened, that that person is "in on" the "conspiracy? Would that apply if the person is forced to sign an NDA to keep his or her job?
"There are no obituaries recorded for the ME and Deputy Coroner, thus I infer they're both alive. What additional information might you have? This image shows below that "Fuddy" was replaced by a military-trained diver, for which there's also copious other evidence.
This shows the way each of "Fuddy" and the replacement diver lay above and below the water.
"Guesses" should not be confused with "I *think* I know."