Uninstalling

Deactivating removes the drop-in, takes WP_CACHE back out of wp-config.php and clears the cache. That is not optional: a site with a deactivated cache plugin and a live drop-in serves pages that nothing is purging. On a network, deactivating on one site clears that site's cache and stops it being served from cache at all, and the drop-in stays for the sites still using it. Deactivating it for the whole network removes both for every site.

Deleting removes your settings only if you ticked Delete all data on uninstall. The cached pages go either way — they are a derivative of your site, not data. So do the plugin's working notes, on every site of a network: when the preloader last saw each page cleared, what was last seen of the cache in front and asked of it, the pages waiting to be passed on to it, and the answers kept for the people who pressed a clear or made a change.