My old colleague is a talkative person

It seems from your words, this was your ex-colleague who stirred contradictions between you, workers, and your boss. Such persons are manipulative, want to manipulate others by gossip, having a bad tongue about everything. They are usually jelous and mean, full of ill-will. It is a pity your boss' wife speaks to her. Perhaps it is in the past tense: spoke to her. I think it is best to avoid such kind of persons as much as possible. If they challenge you, tell them: "please bring the person to me who allegedly told this and that". Of course, they will never do so, because they never go face-to-face. Probably the whole bad story was just their invention and they related it to you as absolute truth. Do not be afraid of them! It is very important. If you fall in, they'll try to manipulate you as well. Do not listen to them, just walk away. Make them understand you do not believe them and they do not have power over you. You need your allies, you, too. Make friendship with such colleagues who deserve your attention. Make such a gossiping person understand you are in majority and he/she is alone.

argh, i hate this type of person. it seems to me that they don't have enough problems on their own that's why they keep messing the lives of the people around them. honestly, it is difficult dealing with this kind. they won't take any words from you because their minds are set that they rule the world, that they can control everyone. what i can advise you though is just to stay away from them. it's a good thing that she is no longer in your office.

Well, talk to your friend that she reach boundaries and need her to stop.

I have never been in this situation. It seems she is still in contact with you also. If she is not a close friend (which it doesn't sound like she is), I would just let her go if she starts talking about the other workers, and not say anything. If she says anything about your not commenting just say you don't want to be caught in the middle of anything.