My input on some of these points:
The collapse of Bitfinex and Tether as a result of fraud.
I don't think this would have an effect on Bitcoin's
long-term future. It might lower people's confidence for a while, but the only thing that would stick is opposition to "pegged" tokens. Mt Gox did not kill people's confidence in BTC completely, as we can see now three years on. Bitfinex also has a much lower share of the exchange market.
Capital inflows drying up for ICOs as funding channels become constricted through regulations, leading to a significant market decline led by Ethereum.
I agree with this point. Even though it doesn't affect Bitcoin directly, ICOs are part of what has stirred up the crypto hype in general and the talk of Bitcoin being a "master crypto" has caused its value to rise along with others, so it could potentially fall with them too.
It's also possible that if they were less accessible for investment from ordinary people, those ordinary people also wouldn't be pushing up the value of the token after it's released, in which case richer investors might be less compelled to get involved as well.
Blocking of fiat gateways that enable cryptocurrency exchanges to operate, effectively cutting crypto off from the real world.
In the Western world and in most other places, I don't see this as an immediate threat.