Secret To Creating New Pages for SEO

Hi everyone,

I was wondering if there was a specific way to create new pages specifically for SEO.

I'll be using wordpress.

My website is organized like this:
I have a homepage that splits my traffic into 5 different pages. Each of these pages sells a different product and targets different keywords.

I'm going to create numerous new posts to link back to each of the 5 pages.

1)Is this a fruitful undertaking or am I wasting my time? How much of an impact will this have on SEO?

1)Are posts different from pages for SEO purposes on wordpress?

2)How long should each post be in order to make this work

3)Should I link every post back to one of the 5 pages, or should I link the posts to each other, creating a sort of an internal link wheel.

4)Is it a problem that my posts are in the blog directory. Another words, the my website looks like this:

homepage.com
homepage.com/product1
homepage.com/product2
homepage.com/product3
homepage.com/product4
homepage.com/product5
homepage.com/blog

The new pages would all be created from homepage.com/blog. So the new pages would appear like:

homepage.com/blog/newpage1
homepage.com/blog/newpage2

It is it a problem that the new posts are all in this subdirectory instead of in the root folder?

Thanks for the help guys.