Please refer to the answer above.
It is certainly difficult to imagine any of those characters in the position that Kurtz had maintained for so long, and this could be attributed solely to Kurtz' charisma and skill at gathering ivory. However, there are a few clues given in the text that might put evidence behind such an answer.
In the book, the three characters are made known by small descriptions that would imply their inability to take on the job that Kurtz has:
The Lawyer: "the best of old fellows—had, because of his many years and many virtues, the only cushion on deck, and was lying on the only rug." (beginning of book 1)
The lawyer is in a position of comfort. He needs a cushion and a rug to be comfortable, and if he were out there, he might be affected by a term of service in a similar way to Kurtz, who essentially lived like a king among the tribe he had befriended.
The Accountant: "had brought out already a box of dominoes, and was toying architecturally with the bones." (beginning of book 1)
This description functions symbolically. Because the accountant is "toying" with the dominoes, which are traditionally made of ivory, he is shown to already have an attachment to the ivory that is traded from the Congo. Indeed, he might be affected in a similar way to Kurtz because of his childish "toying" with ivory.
The Director of Companies: "... was our captain and our host ... On the whole river there was nothing that looked half so nautical. He resembled a pilot, which to a seaman is trustworthiness personified." (beginning of book 1)
The Director of Companies is probably the most viable candidate for being able to take on the Kurtz' role and not be affected in the same way. He appears here to be a sort of pure figure, and might be able to avoid being affected the way Kurtz was.
However, another important quote here is this: "All Europe contributed to the making of Kurtz" (book 2, page 29). In a way, the way Kurtz is affected by his term of service is a symbol of the madness that enveloped all of Europe. From this quote alone, it would be possible to say that there is no man in Europe who would not be affected the way Kurtz was.