As you already mentioned, the most secure children of Napoleon are Reichstadt and Walewski. There are no doubts on Walewski, I would say, not only because his mother visited Napoleon on Elba with their son etc etc. Count Walewski was not only very similar in his looks to Napoleon, he did also have the same voice. On a special occasion (funeral), where Walewski was speaking an old general of the dead emperor broke down with the words: "I would never have thought to hear that voice again!" That explains everything I guess..Despite of the clear fact that Walewski was Napoleons son, he never liked to tell openly about it, obviously to save his mothers fame. One day somebody told him about his similarity to his father Napoleon and count Walewski shall have answered: "Oh, I didn't know that you knew the count Walewski that well!" (He ment his mothers first husband with that!)
I don't what, how exactly it was, but Napoleon also supported him with money, and he inheritated also things of Napoleon. The todays descendants still have a lot of napoleonic things at home...
Even the count Léon is said to be surely Napoléon son, even when his mother Eleonore Denuelle was the lover of Murat as well, and so also Murat could have been his father. At the court of Napoleon III he was often supported with money, but as he was a player, he often lost money and got knew new one again by his cousin Napoleon III and his brother Walewski. He was rather considered only as similar to Napoleon from the looking, but not in his character (he was not such a military genius for example, the same with Walewski).
On the tomb stone of the last count Léon (1911-1994) there is clearly mentioned that he is the great- grandson of Napoleon, but who knows the truth....
The other speculated children are the following:
* Émilie Louise Marie Françoise Joséphine Pellapra von Françoise-Marie LeRoy
*Karl Eugin von Mühlfeld von Victoria Kraus
*Hélène Napoleone Bonaparte (1816–1910) von Gräfin Montholon
* Jules Barthélemy-Saint-Hilaire (1805–1895)
But one has to be very careful with it:
1) The Pellapra story is not proved and by many historians rather considered as pure fiction, many hold the opinion that this lady was making up famous ancestry for herself. Especially because there is no proof at all that her mother was really having an intimate relation to Napoleon at the time, when she became pregant. So she will rather be from her mothers husband, I would say, but not Napoleon's daughter.
2) The Victoria Krauss story is something completely unknown to me. I tried to find out more about an alleged illegitimate son of Napoleon by that austrian lady, but I could't. Until now I only found the dates and not more. It would be wonderful, if someone might know more about the backgound of that. On a website in the net I read that somebody wanted to name further sources, but I didn't find it anymore. So until now I don't have any further details...Help is welcome!
3) The thing with Helene is speculation as well, as far as I know. It is connected with the murder theory of Napoleon (in which I do not believe in any way)
4) This is also someting quite strange. St. Hilaire shall have written in an own biography that he knew that Napoleon was his father, but he does not name his mother. He also told that both shall have been ashamed to talk about it openly and so on. I don't know what to think about it, i personally do not believe that Napoleon was St. Hilaires father, because there are too little facts.
Apart from those I did not find any other speculated children of Napoleon, but if you could find the book, and there might be others as well, I would be interested.
I had a recent contact with a german historian and genealogist, who is working at a complete genealogy on Napoleon and all his alleged children. and even about the bastards and alleged bastards of the brothers. etc I'll write to him again to ask, when his book will be published. I suppose it will be very interesting, because the man is a very good & well known genealogist, able to lead back all famous and not famous families to people like Karl the Great and so on...!