re: Pages order
There are two approaches.
1. If you have only pages in your horizontal menu and that' is all you want in it see here to use numerical order. http://en.support.wordpress.com/pages/page-attributes/#order
2. Creating a Custom Menu http://en.support.wordpress.com/menus/#creating-a-custom-menu
Adding Pages http://en.support.wordpress.com/menus/#adding-pages
Changing the Order & Creating Sub-Menus http://en.support.wordpress.com/menus/#changing-the-order-creating-sub-menus
Custom menu Troubleshooting – My pages are in the wrong order
Check the sub-pages themselves to see if you have established a Parent page and child page “hierarchical structure” in the page attributes module. Remove if required.
Also remove any “order” numbers you have assigned that may conflict with the order you are creating by dropping and dragging. Or simply change them so they are the same order as you establish in the menu. Establish consistency – problem solved.