I've trimmed your post to just the bit I'm interested in, sorry.
I know I'm going to regret this, but. I watched a serious science program on BBC4 recently (I used catch-up, so it could have been ancient. It might have been "Inside the mind of Einstein", but I can't remember) and it made the case for gravity not existing. They tried to explain this position as (paraphrasing), It's not gravity, it's acceleration. To me, it sounds like someone is confusing cause and effect. In my world, gravity causes acceleration. In his world, acceleration causes us to infer gravity. Please don't ask me to explain it, it did my head in. The basis for his argument went like this. Imagine a box floating in space with a man inside it. The man cannot see out of the box (think of a traditional lift carriage) so he cannot tell if he is moving. He will not know if he is in a gravity field (falling at the same speed as the box) or not. Until the box begins to accelerate (let's say upward) . At this point, he will not know if he is in a gravity field or just a box accelerating upwards, because the effect on him would be the same (the floor pushing up on him). There is no way of telling the difference. I would suggest you think about it, but there aren't enough psychiatric beds available in the country to deal with the consequences.
In other news, centrifugal force really doesn't exist. It is just Newton's first law of motion. Now, Newton I get. Einstein, on the other hand, is completely beyond me.