Don’t know about 1 and 2, but as far as #3 goes, remember that when you first signed up for Facebook or Instagram you agreed to a Term of service that allowed Meta access to and use of anything you did on their sites. And if you read the Terms you’ll see that the only way you can change that is either by getting written permission from Meta for the change (HA!) and if you don’t like it, close your account.
You can rest assured that just about every word of publicly posted text on the internet is being used by somebody on some model somewhere. Including these posts.