Ok, I am on my way to answering my own question.
I read through this blog and note that a split cannot occur just because it will lower the tax burden.
This is very dangerous with a Determination Letter request where the question is about a
single capital LOSS, because that the IRS would allow me to apportion that (entirely) to
my NRA spouse.
The real issue is what happens when there is a GAIN (in $US terms). So we need to reopen the joint accounts and buy something (and get a GAIN).
Our purpose is solely to avoid Probate if the spouse predeceases me (through the mechanism of joint-ownership of the stock)--the NRA spouse (who is supplying the funds) already does not pay USA taxes on the gain related to the sale of a non-USA security.
But the IRS may not be able to rule in my favor, even though this is prudent estate planning.
