Sequel Pro 1.1.2 + MacOS Mojave 10.14.5 + MySQL 8.0.16 (Homebrew) have a problem when trying to connect to local (and ONLY local) databases. It pops up a feedback dialog and a never ending progress bar. There is no problem when working with remote databases.
There is a bug report in their Github project page, but it looks like they closed it for being a duplicate... and closed the duplicate as well!
Just use Sequel Ace, an active and amazing working fork with the same UI/UX of the legacy Sequel Pro