A chain of changes in the past

I have a very simple question.
When changes are made to the law retroactively, does this perhaps open up a chain of changes and require a careful examination of them?
Some sages canceled a kiddushin retroactively for some reason, for example, he sent a divorce and canceled it.
The same woman, during her marriage, received a Kiddushin from someone else. Now she suddenly is consecrated to him? And are the children born to her by her original husband after the Kiddushin to the second one bastards? Or do the Rabbis rule that out as well?
That man, after sanctifying his wife, went and sanctified her sister. Now her sister is sanctified to him? Or do the Rabbis also invalidate that?
The father of that woman, a professional, taught her husband, who was his son-in-law, the secrets of the profession because he thought he was his son-in-law, and clearly he thought so. Now that everything has expired, can he demand tuition from his son-in-law? He gave him gifts as a son-in-law, can he demand them back? The son-in-law fed his wife's father for free, will he now demand payment?
A lot of people did all sorts of things based on the fact that these two were married, explicitly or implicitly, and now it's all null and void?

The question is whether when our rabbis perform kiddushin, they also arrange everything that is needed around them, perform kiddushin and give away things and give what is needed to whomever is needed in order to isolate the confiscation so that it will not have any repercussions outside, or whether there are repercussions and if they know about the repercussions, they should address them. If they don't know, then there are doubtful and strong laws and they should bother to find out, etc.