You’ll get 1% of the entire firehose. If the total coverage of #abc is < 1% of the firehose at the time, you’ll get all of the results for that query.
You cannot get Tweets from deleted user accounts.
Language is a separate issue. You cannot get deleted Tweets from the Streaming API, but you will see deletion notices for existing Tweets (and you must then delete them from your app’s data store, per the developer policy)