Wordpress internal and external linking including categories

Good evening,

(slightly long)
To the point, here is what I am trying to figure out and I hope someone may have some insight:

I am setting up a word press blog for the various articles that my shopping cart has set up (that I wrote). The goal here is to take the articles off of my shopping cart (with 301s of course) and instead have all of my articles in education.domain dot com.

I believe based on my SEO knowledge that it would be better to isolate the articles in word press and then link the articles to their relevant category product pages as opposed to what I currently have set up, which is each article has the products category list on the left, essentially linking all articles to all of the products main category page.

Ok, so now you know my goal, here is what I am trying to figure out:

Lets say I have about 20 categories and at the moment 1 article for each category. Many of the articles have a paragraph or two that talks about another relevant topic in another article, so naturally I would want to link to that article within that paragraph using appropriate anchor text (at least to my understanding.)

Now, do I also put that article in its respective word press category AND the semi-related categories, meaning the categories that are directly related to the articles I am already linking to? Or just link to the articles?

I started setting word press up to have each article tie to any category that slightly relates to it, but looking at the sites front end and seeing how the archive worked it just seems a bit redundant and may affect my overall SEO.

Thoughts?

nobody has any insight to this?