Add a new page with the list of posts

And if I wanted to reverse the pages?

I would go back to the original home.php file and change the logic around so you end up with this:

<?php if ( ot_get_option('blog-standard') == 'on' ): ?>
	<div class="post-list group">
        <?php $i = 1; echo '<div class="post-row">'; while ( have_posts() ): the_post(); ?>
            <?php get_template_part('content'); ?>
        <?php if($i % 2 == 0) { echo '</div><div class="post-row">'; } $i++; endwhile; echo '</div>'; ?>
	</div><!--/.post-list-->
<?php else: ?>
	<?php while ( have_posts() ): the_post(); ?>
		<?php get_template_part('content-standard'); ?>
	<?php endwhile; ?>
<?php endif; ?>

Then, the front page will always be displayed based on the status of the Standard Blog List and the other page will be the opposite. You can change them by switching the Standard Blog List option.

And if I wanted to use two css files, one per page?

You could enqueue another css file but they’re not page specific. You’d have to write a function or some other logic to determine which page you’re on and then enqueue the desired file. Doable but not something I would recommend. Far easier to just set the styles to target specific elements based on a body tag class; “archive” for the front page, “blog” for the other page. Just remember that whatever styles you apply to the front page will affect every other category, tag, author, etc. archive page.

One way around that might be, in page-title.php, where you modified this section:

<!-- if displaying the blog Home page or the static Front page -->
<!-- query var 'error' is set in function 'my_front_page' -->
<?php if ( is_home() || get_query_var('error','') == 'myfrontpage' ) : ?>
    <h2><?php echo alx_blog_title(); ?></h2>

Change it to add an empty div with an id on the front page so you can identify it:

<!-- if displaying the blog Home page or the static Front page -->
<!-- query var 'error' is set in function 'my_front_page' -->
<?php if ( is_home() || get_query_var('error','') == 'myfrontpage' ) : ?>
    <!-- if on the static Front page add an unique id -->
    <?php if ( get_query_var('error','') == 'myfrontpage' ) : ?>
        <div id="my-front-page"></div>
    <?php endif; ?>
    <h2><?php echo alx_blog_title(); ?></h2>

Here’s how to handle identifying the front page:
1. Copy header.php to your child theme
2. Locate this line near the top of the file:

<div id="wrapper">

3. Change it to this:

<div id="wrapper" <?php if ( get_query_var('error','') == 'myfrontpage' ) { echo 'class="my-front-page"';} ?> >

Now, when the query is running on the front page, it will add a class to the wrapper and the wrapper div will look like this;

<div id=”wrapper” class=”my-front-page”>

You can target the elements on that particular page using #wrapper.my-front-page.