The Testimony of Christ comes from the Holy Ghost and is directly related to the Baptism of Fire. It is the gate by which we enter. The fire is the cleansing agent by which we are cleaned of our sins or impurities. The Telestial are judged by Works, but the Terrestrial are not, they are covered by the atonement while they progress toward the Celestial Glory.(See D&C 76) The Terrestrial are on the path but have not completed that path and received a crown, which happens at C&E, and comes by knowing God and Christ who he sent. A person who is baptized with Fire and the Holy Ghost does not necessarily know God and qualify for the CK. They believe or have reason to believe and are working on faith, not knowledge.
Can you receive the Spirit without Baptism? Yes, One such person is a young girl who is being raised under the higher law, like the children who will be born in the millennium, “without sin to salvation”. At 11 years old, she had not been baptized and has the spirit as much as or more than most. There are also a number of protestant preachers who do and have experienced a number of the gifts of the spirit.