Centering Page Menu bar, not having categories appear and page slugs questions

Hello,
I have looked around in the forum for a while and not able to find the answers.
I am building a website with WP-atahualpa but will not be using it as a blog, so , there may not be posts and comments etc. For this how do is get rid of Categories, Archives, Recent posts etc from the side bars?

If i do plan to keep those things but dont want it to call categories, how do i change that language to something else?

Currently i am doing everything with Pages. However, i am not able to get the easy url for the pages like /about /events etc. I looked in permalinks but not able to set it for pages. I dont have access to .htaccess file. what are my options?

My header image is not rotating even though i enabled it in options.

my site is http://www.championstrophytampa.com/ (still playing around with it) i want the page menu bar items to be centered instead of being on the left side. I will be adding a few more menu items butll would like it centered.
I would appreciate the help.
thank you.