Does this extension allow category-wise selection of products for the Facebook feed?

Yes, <a href="https://www.magedelight.com/magento-2-extensions/facebook-shop-integration-magento-2.html">Magento 2 Facebook Shop Integration Extension</a> allows you to select a certain products to display on the Facebook feed.

Will this extension come with CSV-based mapping?

Yes, with Facebook Shop Magento 2 Integration, mapping becomes easier and quicker than ever.

How does the feed generation takes place in Facebook Store Integration Magento 2 Extension?

<p>This extension offers manual as well as CRON-job based feed generation facility.</p>

Can I schedule the feed generation process?

Yes, the extension allows you to schedule the feed generation process via CRON-job. Read the Facebook Shop Integration for Magento 2 extension's configuration guide to schedule the feed generation process via CRON-job.