Though he worked with Paul at Rome he still traveled doing missionary work. Where was Titus at the time Paul’ wrote 2nd Timothy?

He went to the Roman province of Dalmatia. Today it is part of Croatia and other Balkan states.

Source: 2 Timothy 4:10

Titus traveled with Paul as aide and assistant for years, what Great Church council did they attend together?

The Council of Jerusalem, where it was determined that gentile Christians did not need to follow the Jewish practices. See Acts 15

Source: Galatians 2:3

During one of Paul’s Journeys he left Titus at Crete. Why did he leave him there?

To organize the church there and appoint Elders for every city. He was the First Bishop of Crete.

Source: Titus 1:5 and 3:15

Was Titus a Jew or Gentile believer?

Unlike Timothy Titus was a Gentile believer. Paul would not circumcise him.

Source: Galatians 2:3

Titus was one of Paul’s closest friends in his work. What church did he take a stern letter from Paul to?

He was Paul’s intermediary to the church at Corinth.

Source: 2 Corinthians 7