Placing assets for external use

Question

I'm developing a plugin, that is meant to work on external requests to a wordpress site.

The plugin will generate a .json file, and will come with 2 default .css style and 1 .css file that will contain the common styling rules (I will combine them later).

My concerns stands at, where should I place the files and is it safe to create a simlink between plugin's assets folder and where the .json file is generated at.

Plugin folder structure:

plugin/
      assets/
            common.css
            blue.css
            clear.css
      plugin.php
      plugin-class.php

And were currently the json file is generated:

$dir = wp_upload_dir();
$dir = $dir['basedir'].'/plugin';

WP_Filesystem();
global $wp_filesystem;

if (wp_mkdir_p($dir))
     $wp_filesystem->put_contents($dir.'/latestArticles.json', 'callback('.json_encode($toExport).')', 0644);

On a future release, I will allow the possibility for the files to be uploaded to a S3 Bucket, but meanwhile, I am currently placing them to the path mentioned above, mainly because all may requests to mm.site.com/... are going through CloudFront

So, I am asking that if is safe to have (or recommended) a simlink from site/wp-content/plugins/plugin/assets/ to site/wp-content/uploads/plugin/assets ? If not, where should I place my file, so they can be available from external requests?