Sweet. I think we've got it! It didn't take as many changes after all.
Here's the solution for anyone else who wants to use the regular category pages with the grid portfolio layout in the Angular theme. You may also be able to take this same idea and adapt it to change the archive page, blog, etc. (Note: this takes some familiarity with PHP, so do this only if you know what you are doing!)
1. Create a new category.php file in the angular theme folder
2. Copy the entire content of the file "template-portfolio.php" in the theme folder, and paste it into the category.php
--- Now, since there are no options for category pages, we have to insert the options manually into the category.php page.
3. Go to about line 18 and replace:
$avia_config['new_query'] = array("paged" => get_query_var( 'paged' ), "posts_per_page" => $avia_config['portfolio_item_count'], "post_type"=>"portfolio");
WITH
$avia_config['new_query'] = array("paged" => get_query_var( 'paged' ), "posts_per_page" => 24, "post_type"=>"post");
(You'll notice that we simple are manually inserting the number of posts to be shown on the page (24 in our case), and changing the post_type to "post" instead of "portfolio".)
4. Line 24 - Change the number at the end to the number of columns you would like in the grid. We chose 3, so the new line looked like this:
if(empty($avia_config['portfolio_columns'])) $avia_config['portfolio_columns'] = 3;
5. Line 38: Replace the "<?php echo $avia_config['content_class']; ?>" with "twelve alpha":
<div class='content <?php echo $avia_config['content_class']; ?> units template-portfolio-overview content portfolio-size-<?php echo $avia_config['portfolio_columns']; ?>'>
CHANGES TO:
<div class='content twelve alpha units template-portfolio-overview content portfolio-size-<?php echo $avia_config['portfolio_columns']; ?>'>
6. Now we need to remove the sidebar, which usually would appear. Go to about Line 68 and remove the following:
if(strpos($avia_config['layout'], 'sidebar') !== false)
{
//get the sidebar
$avia_config['currently_viewing'] = 'page';
get_sidebar();
}
7. Find the file "loop-portfolio.php" in the "includes" folder inside the angular theme folder. Duplicate this file and call it loop-category.php.
Go to Line 136 and change the following:
if($loop_counter > $avia_config['portfolio_columns_iteration'])
TO
if($loop_counter > 3)
(NOTE: Here we are simply manually inserting the number of columns we have once again, so we inserted the number 3. If you want 2 columns, this number needs to be 2, etc.)
8. Last, go back to the category.php file and go to Line 58. Change the following:
get_template_part( 'includes/loop', 'portfolio' );
TO
get_template_part( 'includes/loop', 'category' );
(This tells the category page to grab that new loop-category.php file we just created, instead of the loop-portfolio.php).
That's it!
We are continuing to test this, but we have not seen any issues yet. Feel free to add comments, corrections, typos you find, or other helpful things below.
Thanks!
Create a new thread and tell me what problems you are encountering and what you want to know. 
There is no step 3 :) 
