You write, "You could try 'Napoleon ll: King of Rome' by EM Oddie (date not stated). There may well be more up-to date works but that is quite comprehensive, no footnotes but a decent bibliography. The report on the boy's health made in 1830 is given in detail and makes it clear that his chest was affected at that time even though his doctor did not suspect TB."
Susan, I have no interest in N. II or his death.
By chance, Franz II/I and the Habsburgs have been a major subject of study (the military airgun thing, of course.) As a result, I have a pretty good picture of who these Habsburg folks were. Much of my work has involved tracking down events where there are Habsburg cover stories placed in papers around Europe. The only working morality of the Habsburg Monarchy was it's continuance.
There is no whitewashing of the Habsburgs. The correctness of "The thanks of the house of Habsburg" (that is, being stabbed in the back) is indisputable. What did Franz do when N. approached Vienna? He ran... twice! After offering all support to the Tyrolleans in their uprising 1809, what does he do? He surrenders Tyrol to the enemy without a thought. No bigger skunk in the world than Franz II/I.
Any reasonably objective study of the death of N.II has to include Franz II/I on the suspect list.