Rob's advice is very good in regard to sending people to the more effective inner page.

I would not mess around with canonical tags, unless the content is actually duplicated.  Rethinking your internal links might be helpful.  One thing I have done in similar situations is to use a keyword anchored link from the category page to the home page.  Moz Analytics will tell you this is keyword cannibalization, but it does often work to nudge Google toward ranking the home page.  So on a page about "Red Widgets", you could link to the home page with "Red Widget Company".  What is likely to happen is that you will sort of split the searches based on user intent, and searches that are more than just the base keyword. Searches that Google thinks are more informational would go to the Red Widgets page, where someone looking for a supplier or maker of red widgets might be sent to the home page.  Similar links throughout the site where they are appropriate would also be good.  Like, if you have a page or a blog post that mentions red widgets, link to the category. If it says something about manufacturer of red widgets, link to the home page.  Just like incoming links, you don't want to overuse the same keywords, though.  Mix things up a bit within the same topical theme (red widget maker, manufacturer of red widgets, red widget company...)

You may be over-thinking this, or taking that "one keyword per page" advice too seriously.

You are right that you should accurately describe the category page, and using that keyword (and anything else that accurately describes the topic) is going to be part of that. Since that page is the one that is actually about the category, I would not un-optimize it.  I wouldn't even worry about removing the keyword from the home page, either, since it is also relevant. You may want to link from Home to the category where that keyword is used, though I don't think that would make a huge difference.

The good news is, you just might end up with both showing in the SERPs.

1. If you are talking about the meta keywords tag, don't bother. Google and other search engines don't use it for anything that would benefit you.

2. Does putting those words in bold do anything to benefit users, or are you doing it because you believe it will bold words somehow help improve your position in search results? If it makes something more clear to users by making certain words bold, and doesn't look ugly or stupid, then do it. If there is no benefit to your readers to have seemingly random words in bold, then don't do it.

"LSI" is just a fancy term for synonyms, which are something any writer (SEO or not) should be using so your writing is not repetitive. "Long tail keywords" is just a fancy term for "things people actually search". Write naturally, and think about how people speak and write if you want more "long tail" search traffic.

You could try using https://www.google.com/webmasters/tools/submit-url?continue=http://www.google.com/addurl/ to submit the URL to google, but if the page can only be found by using their locator, it may not get indexed since it is not linked within their site.  Worth a try though.

Backlinks from adult sites?  Just kidding. That probably refers to a raw URL like http://yoursite.com rather than one with anchor text.

Noindex/nofollow should be good enough, but if you want to be sure it doesn't get indexed, you could can also include <meta name="robots" content="NOINDEX, NOFOLLOW"> in the head section of the page to be blocked. You can also exclude the page in your robots.txt file. </meta name="robots">

You can find a simple robots.txt generator in Google Webmaster Tools if you need to block particular pages or directories. The robots.txt file should be in the root directory of your site and look something like this:

User-agent: * Disallow: /file-you-want-to-hide.html

You can also request removal of specific URLs in Webmaster Tools if it has already been indexed.