if by "latest" you mean the "rebecca"-release they advertise on their homepage, i got bad news for you. They ship with gtk version 3.10.x. The minimum api needed is 3.14.x . This dependency is available in mint since the "betsy"-release.
i just pushed a fix, so older APIs should work, too. Please pull the git and try to build again. Thanks for the hint :)
Yup except for the large image, you got everything right.
The large image _was_ the topmost suggestion of autocompletion at the time. This one in particular was "search the string in the url-bar with duckduckgo". It does not exist anymore. It has been replaced with three neat columns that organize suggestions in a better way.
Contributions are very welcome :)