No he hasn't, although he did play for Barcelona.
He is in his second season with Turkish team Fenerbahce.
Yes, he does.
No, Ronaldinho does not play for FC Barcelona, he plays for AC Milan
No, Ronaldinho was not selected to play on Brazil's team for the 2014 FIFA World Cup.
Ronaldinho plays for AC Milan as the no. 80 since 2008.