You could put a snippet or summary of the article on the relevant product sales page and then link to the full article on a blog page. On the blog page have links to related products that takes them to the sales pages.

You might want to place a brief review on the sales page, but I would put any articles on the blog page.

It will add a boost to that product page. While you are adding a brief description within the product, search engines are more likely to give it higher ranking.

Putting reviews and articles with product would actually be nice... This helps in visitor making his mind and generating more leads.

Since your client generate unique articles , its very easy for you and you should convince your client and find long tail keywords which drives lot of traffic . Put a snippet on review page and point it to your blogs. Also in blogs make sure you have a opt-in form or a pointer towards your sales page.

Never miss out the long tail keywords

Reviews will definitely work but make sure the content isn't spammy or low quality. Don't overload the page with content either because this will put customers off