As this article is not about Davout, but about finding the grave of Gudin, I don't see any problem with saying the following:

'Researchers used the memoirs of Louis-Nicolas Davout, another French general of the Napoleonic era, who organised Gudin's funeral and described the location. They then followed another witness account, which directed them to the coffin.'

Davout was 'another French general of the Napoleonic era' was he not? So what is the problem here?