I think people who are closely related and are on bad behavior should be invited to the big events where lots of people will be because at those events, you will have a buffer of people. And then it does not further any rifts. There are people invited to family weddings that are not expected to come (great-aunts and uncles who are 90+ and live in other states - we would be delighted to have them, but there is a 99% possibility they will not come), and an cousin that has been on the outs. I wish this cousin would come back into the fold whether they are a pain or not. They are not invited to intimate parties but are always invited to weddings, larger celebrations, family reunions and they have never even RSVP'd to decline.

I would have opted for them to come to the shower, with a family member assigned as a buffer just in case, vs inviting them to your home.