ad 3. You are buying overpriced Bitcoin, because they are "special". Oh, yes, that is really sane
You don't need to buy a whole bitcoin, few satoshi is enough. You won't notice this purchase even if you pay 1000-fold.
ad 4. What if, there are just small unknown exchanged, that work with the weaker chain? How long does it take to register there?
Ever heard of off-exchanges trades?
ad 5. Selling your Bitcoin is always risky, especial if you exchange them for another cryptocurrency.
Selling your Bitcoin is always risky? Not for fiat, last year clearly showed that those who sold did a smart move. I hope you won't try to argue that keeping bitcoins during a panic is a smart move."There is no free lunch", if someone tells you otherwise, he has no idea, what he is talking about or is trying to scam you.
Agree on that.
I argue, that you might miss the price increase and have to buy Bitcoin at a much higher price--> there is just a too big risk in there.
Yes just keeping your Bitcoin is a much smarter move, instead of playing casino with them.
Off-exchange trades don't change anything about, that you have to find such people.