1. About font size on publisher!
Go to CP > Main » Customize design » Editing templates >> Publisher > Page with full text and its comments and find something like this
Now add style to the link
So that it looks like this
<a style="font-size:12px" href="$ENTRY_URL$">$TITLE$</a>
You can change font size by changing 12px
In the same template you can add what ever you want where you show your green line, it is at the bottom of this template
2. Because there must by the active class, it's hard to make active menu, I suggest to remove active class from Home button in menu!
3. Go to CP > Main » Customize design » Editing templates >> Page editor > Site pages and remove
From your code, content will be in center!
It's hard to make something on costume templates I suggest you to work with uCoz default templates for some time to have skills