how can i get rid of old apple id's

There are probably some Apps in your backup that were downloaded with those Apple IDs, and is now asking for them to download them as Apps are forever tied to the Apple ID that downloaded them.

Also is there any reason you keep making Apple IDs? Its strongly recommended to only have one Apple ID, and keep it updated to a new functional email if the associated email address expires or is no longer functional for any reason.

You have to delete everything what was downloaded with an other Apple ID.

If you get the message 10 times that means you have 10 apps downloaded with an other Apple ID

You have to delete them and download them again with the Apple ID you want to keep

You can't. Only Apple can do that. You can simply stop using them.

That is because they are still logged into by some or all of your devices. Log out of them and they will not pop up anymore.