My experience (which may not be typical) is that it does not hurt to have more than one page with the same keyword and it may help, provided they both link to each other and are not duplicate content, and even if they do not link to each other. The new page may be listed beneath and indented from the old page. It may help if the new page has a variation of the keyword. EG if page A has Paris: Hotels then page b can have Hotels: Paris.

You might have a dozen pages with equivalent content and optimization and find that one really takes off, while all the others are so-so, and there is no rational explanation.

AFAIK keyword density does matter. IBP thinks it does and I have generally found that it helps. Likewise, unless the raw density (including stop words (common words that are not indexed supposedly) exceeds 10% which is absurd, higher density does not seem to hurt - it is usually essential.

Adding 1 link on 1 page is not going to do much - BUT - one way that often works to get a page to stand out from others on your Web site is to repeat the link to that page on every page of your site. Obviously, if you are doing that for both pages, one of them will suffer for that keyword.