I agree on your first two points after that not some much. First we agree if you adjust the trigger too light you can trip the first sear by slamming the action shut. Second we agree if you hold the trigger back and you lower the trigger manually the hammer will be resting on the firing.
Now for the area of disagreement. Jarring or pulling the trigger when the hammer is down does not result in the hammer resting on the firing pin.
When the hammer is down the hammer pressure is also holding the hammer block in place. If you pull the trigger or it is jarred off the hammer block is still in the up position holding the hammer of the firing pin. In this condition if you remove the hammer pressure from the hammer block the hammer block will retract and now the hammer will be resting on the firing pin. I tested this in the early 70's and due to this I opted for a full cover shoulder holster for hunting. Since that was a long time ago so I just tested a couple of mine to ensure my memory was correct.
The hammer also needs to be pulled to lower the hammer block. If the trigger is not pulled the hammer slipping when cocking will not fire the gun since the hammer block remains up.