About the second question. Trading the ETF directly will not have effect on bitcoin price, what will have effect on bitcoin price is if more people are buying the ETF shares and then the company that are providing it are buying more bitcoin when there are needs for it as more people are demanding for the ETF. As the company are buying and holding more bitcoin, it will make bitcoin scarce and the demand also will make the price of bitcoin to increase.
I expect that they will force market makers and other institutional participants to buy huge amounts of real BTC in order to back new shares of these ETFs. This buy is going to pump the price of Bitcoin into the hundreds of thousands I believe. I advice everyone if you can, don't buy a spot Bitcoin ETF don't buy the Black Rock one and don't buy any of them. Instead earn the real BTC, hold it in cold Storage or a software wallet yourself that way you can both benefit from the price pump and also not get rugged eventually along with all the other Bitcoin ETF holders.