Semicolons - hyphens -commas Help

Please can someone help me with the following:

1. Sarah wanted her life to be remembered; therefore, she staged a pageant. (Should there be a comma after Sarah? And should I put a semicolon after remembered?)

2. A first class employee is: dependable, loyal, and efficient. (Since first class cannot be separated, shouldn't it be joined with a hyphen? Also should a colon be used after is?)

Thank you so much in advance.....

Oh, I almost forgot... Yes, 'first-class' should be hyphenated, since it is an adjective.
And the choice between semicolon and period is most often up to the writer.