Your question is detailed and needs a complete answer. I believe that I can answer a part of the reason why Steem prices are trading at 7x times the market price.

The thing is that at the moment Bithumb has 85 percent of the trading volume of steem but at the same time you cannot deposit or withdraw Steem from Bithumb.

This has lead to a complicated situation, where speculators are taking advantage of the situation. This means that with high volume of tokens are being traded at place where the supply is low (due to wallet lock down). This has resulted in jacked up prices and higher price volatility. The speculators are feeding this volatility make day trading gains, which in turn is pumping the price.