Hello Ktak1-
Welcome to our forums! Everything that you want done can be done. Here is what I suggest you do:
You can manipulate all the themes... however the themes put in two types of site layout styles.. either actual HTML or what's considered "default", such as the basic category links. You can tell which is used by going into that area of your site (Site HTML > Top of Page editor, Left side navigation bar editor, etc...). If it says "use custom" then HTML is used... otherwise if it says "use default" then the MonsterCommerce default settings are used.
So, if you find the area you are trying to edit is "use default", then here's a quick workaround if you want to change it up a bit. Go to the front end of your site and view the source. It's clean HTML, so you should quickly find the code where the area you want to edit is located. Then copy that code, and paste it into the HTML editable area where you first discovered you were using the default. From here, you can manipulate it as you wish.
You can add style tags to a custom style sheet as well. If you go into your file manager, you should see a custom.css file. You can add styles to this, and then use it in any HTML area you are adding code to.
For your front page, you have one of two options. If you want to keep the main index.asp page, you can, as you say, edit the news and message areas. The area you have the sample product is your home page specials area (Which is found in each product editor as a checkbox). If you do not want that there, do not check any products for home page special, and now the middle section of the front page is all available to edit.
The other option is not using the front page at all, and creating your own index.html page to throw in front of your store. Then, since it's static HTML, you will have full control of every aspect of the page.
Hope this helps!