Help using one WordPress on two pages and creating category-per-user mod

Hello,

I am new to the WordPress scene and need a little assistance modding it to fit my needs. In a nutshell:

Is it possible to make a rule that puts any post a certain user makes under one and only one category every time he/she adds a post?

Finally, I would like to run one WordPress on two different pages, if possible, with the first page only showing Excerpts/Previews of posts categorized as “Insight” (along with posts from other categories) and the second page ONLY showing the FULL versions of posts categorized as “Insight.”

If it helps, I created a pseudo-code workflow as an image below:
https://img692.imageshack.us/img692/449/wppseudo.jpg

I hope these modifications are familiar with some or there are plug-ins out there that already exist for these requests.

Thanks for the help and a Happy New Year!