Perhaps, there should be another way to make a mini version of Firefox like Opera Mini is as Firefox Focus lacks various features like tabs, auto-complete and other common browser features. Of course, it may seem that Google search engine is like too popular among people like people use it to look up online for information they want but in the future release, there will be an option to choose whichever search engine you probably want.
Browsing-wise, you’re in private/incognito browsing mode in Firefox Focus by default but you can export your browsing session to Firefox if you have that app. Another good thing is that you have the options to block ad-trackers, social-trackers and analytics-trackers. Downside is how over-protective the technology can be when it comes to privacy as if the service you’re browsing to may suspect that your account is compromised and especially that certain features on the site may become inaccessible as a result of enabling a block that blocks other content trackers. There’s also a feature to block web fonts but I don’t know the reason behind it.