Is it possible to retrieve the number of retweets from a Twitter comment and the username localization, using TAdvTwitter?
Unfortunately it's currently not supported to retrieve the number of retweets from a Twitter status message.
However this is a good suggestion and we'll investigate if this can be added in a future version of the TAdvTwitter control.
I'm not sure if I understand your question about username localization correctly.
The user's location (if available) can be retrieved from the TwitterStatus.User.Location property.