Right, the 60K is US situs, the (Trump’) 11 Mio is global, both absolute (once you cross 11 Mio comes the relative calc as you showed, only above 11 Mio global you pay at all).
It’s just important to know that one might have to pay estate tax even when having far less than 11 Mio, as this treshold gets lowered to the percentage of your US assets / total assets. This is even before Democrats probably will want to lower that amount again.
The point remains: if you go for (b) your heirs will have to declare to the IRS…whether you have to pay or not… doesn’t matter… they unblock your broker or bank only with the form… that’s what I termed “mess” (after consulting the NZZ article)
Yes, that’s the hassle. I am not quite sure whether only qualified intermediaries rat you out to IRS. Cornertrader, for example, shouldn’t have this status. I assume this since they seem not to give their clients the W-8BEN option.
As for your death scenarios (sad thing), the estate opens de facto with your death (certified by a doctor, he will know when you died) and from there things go legal (involving local authorities, courts, notary, etc.), meaning all of your scenarios are basically fantaisies from an IT guy (no offense) : )
To go on with this morbid turn: In Switzerland, you are dead when a doctor signs the death certificate (with time of day). The people set to receive your assets, in your scenario, would have to liquidate your US-assets before that. Money held in a non-US brokerage is not a US situs asset. Getting the money out is another thing. IB for instance wrote that they would not immediately free large sums, but making checks first, which could take days (at least, I assume).