The `Minimum Number of Items` setting that you've used is the correct one. I'm currently in the process of setting up the same filter (but only with single select) in the exact same version of Sitecore and SXA that you are using and currently it looks like this:

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/zfOHS.png

Have you double checked that everything is published to the `Web` DB properly? 

In our case we had the filter on a `partial design` located in a base site. I've seen some issues where the result was cached and I really had to publish the base site (including the `partial/page design`), all the `datasources`, settings and the site where the page was located. I even ended up doing an `IIS` reset to make sure all caches where cleared.