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Lauren, you should note that the 301 redirects are "Notices" in in the Crawl Diagnosis Summary and not actually warnings.  As noted in the report, Notices are interesting facts about your pages Moz found while crawling your site. As Bereijk stated, your redirects from URLs without trailing slashes to ones that have them is fine.  As a point of information however, such redirects are not necessary, as either version (but not both at the same time) is acceptable but you do want to be consistent in how you deal with them on your site. Your redirects from ugly URLs to "seo friendly" URLs are also fine. The "Warning" regarding Too Many On-Page Links trips at 100.  You might call this a soft threshold, as there is no hard rule held up by Google as what is actually too many but it's been suggested that the lower a page's authority, a fewer number of links are recommended.  Dr. Pete wrote a post on this here: http://moz.com/blog/how-many-links-is-too-many

Thanks! It's been a great help.