Golly gee- another opportunity for me to upset folks laugh What shall I do?

Hardly anyone in the trade actually likes FPE panels- but that's a far cry from the 'sky is falling' panic the sight of an FPE panel seems to provoke in some.

To answer your questions:
1) I am not aware of any low,or code amendment, that 'outlawed' FPE panels in any way.

2) NEC only says to use listed equipment.

3) Who sells FPE breakers?The firm has been out of business for some time. True, there are folks selling used breakers, and there are other makers who make breakers that fitin FPE panels. I doubt you'll ever see a new FPE breaker for sale, though.
In the broader sense, since when did something being illegal make it illegal to sell them? Advertisers in "High Times" have made fortunes selling to the illegal marijuana growing market- and that's only one example.

4) Put up or shut up. That goes for inspectors, too. Exactly what is being said? What's their source? Otherwise, see my answer to #1.

5) Again, put up or shut up. Exactly what is being said by which insurance company? For that matter, 'liability' insurance is completely different from 'homeowners' insurance.

In practical terms, FPE being out of business really puts a bind on their continued use. Replacement breakers are quite expensive, and you can't get GFI or AFCI breakers. Other code issues (like the maximum number of disconnecting means) come into play when you try to expand.