The attributes which make any type of government unique are it's characteristic. As a government form, some characteristics of a welfare state are a benefit and some are not.
I most contexts, no. It can be considered an error if viewed from a programmer's perspective, because a bug is viewed as an error in the code of a program. If it is not viewed from a similar perspective, then it is not a synonym. Thesaurus.com can be a helpful place for you.
One of the main characteristics of Jean-Antoine Houdon's style is that his artworks mainly features "<span>a combination of naturalism and a new classical style." In addition, he was prominent French artist at his time wherein his principles of art made him one of the most influential figures in the Age of Enlightenment.</span>
