My thoughts to your questions:
1) To a great extent, this can be done in post production as long as you keep the camera rolling throughout. What I do is overlap the audio, but cut the video from one person to another - so one person carries on talking,but u get the reaction of another person, then you can cut back to the original person that's speaking or to another person. This way you elimate the movement of the camera from one person to another and it looks like you have multiple cameras. I have an example of this if you want to see.
2) In films this would probably be done by having the camera roll on tracks to make a smooth movement. Obviously you can't do this, but there are workarounds. I,ve heard of people putting cushions in a wheelbarrow, then placing the cam ontop. This can apparently produce good results. Then there's the steadicam, which is again expensive, but there are sites that explain how to make your own on a budget.
with practice though, you can keep the cam rock solid without the aid of a tripod as long as you support the camera firmly with one arm supportiing the other.
3) If you want the best possible sound without using mics, why not record all the audio seperately. just make sure you make a marker to synch the sound! ( apparently that's why they use the old clapper boards in films - and if you notice, now days they also have a timecode on them - i thinks!)
4) No idea whatsoever about lighting!
5) Again, not a question for me to answer
