Does divorce occur upon the husband's statement: "Yes, we will divorce them and marry others," in the context of joking about renovating the place, and is this considered a conditional divorce dependent on the renovation?

There is no difference between the husband saying: "Yes, and we will marry others," or "Yes, we will divorce them and marry others." Both phrases are a promise of divorce, and a promise of divorce is not a divorce and has no legal consequence, nor is it obligatory to fulfill. The questioner is advised to stay away from obsessive thoughts, and the husband and his brother are advised to stay away from joking with the words of divorce, for the Prophet, peace and blessings be upon him, said: "There are three matters, whose jesting is serious and whose seriousness is serious: divorce, marriage, and revocation [of divorce]."