The desktop version of the Firefox browser auto-detects search engine from pages and provide option to add the search engine easily. In the current mobile browser, one has to add search engine manually, and has to provide Search engine name, URL to use for search and Search suggestion API URL in their relative textboxes when adding a search engine. So, it would be nice to have auto-detection of search engine from page in Firefox mobile browser versions to quickly add a search engine.
One user has requested to sync search engines between devices:
https://connect.mozilla.org/t5/ideas/sync-search-engine-settings/idi-p/366
This can also solve my idea as I can add search engine in the desktop browser and it would get synchronized with the mobile browser connected to the same Firefox user account.