Is a man's saying to his colleague, "Look at how happy so-and-so is, and if you see him otherwise, by my honor/by God, I will marry you to my wife," considered a conditional divorce, an immediate divorce, or a type of divorce?

Firstly, swearing by honor is reprehensible and impermissible. The permissible oath is by Allah or one of His attributes. Secondly, your breaking of your oath by Allah necessitates an expiation for the oath, and this occurs if you find the described male colleague to be other than the characteristic you mentioned, and you fail to fulfill your promise to marry off your wife. Marrying off one's wife to another is considered an irrevocable divorce, unless it was said in jest.