Hello,
As long as the content is not identical then you should not have any issues with duplicate content. If the same keywords or phrases appear that is alright, but try not to over due it and mix it up as best you can. As for the internal linking, it is ok to link internally, but again, mix it up. Don't use the same keywords in the anchor text over and over, use different phrases and always, make it sound natural. Focus on the content and don't over optimize your pages.