One conclusion is:
> Not adding the domain to Google Search Console immediately.
I don't understand. What is Google Search Console, and should I add all my domains there right now?
If it's already in the Console when it gets blacklisted, you can appeal it without having to 'verify' ownership of the domain that, in this case, you no longer control the DNS of, because you completed that process when adding it to Console.
> I don't understand. What is Google Search Console, and should I add all my domains there right now?
Google's way of tying real identifies of people to domains, without making it explicit.
Basically, your domain will be weirdly treated by a bunch of entities, none the less Google themselves, if you don't add your domain there (or some other Google property).
Especially with less common TLDs, like .online, they really want to be able to tie it to some identity, so unless you add it there, eventually your domain ends up on some sort of blacklist, in the case of the author it seems they used the "Google Safe Browsing" blacklist to get the author to involve Google somehow.
To request a formal review, you must be a verified owner in Search Console.
Can't answer if you should add them or not...
But if you do - you would get some notifications from Google about that website/domain.
I've only ever seen emails of the "There's an increase in 4xx/5xx errors on site/page(s)"
https://search.google.com/search-console/about. Yes. It gives you options in cases as described here.
Was called webmastertools before.
By adding your site to there you can get data on how many clicks & impressions your site received on google, what keywords it ranks for etc.
You can also request Google to index your site on GSC as well.
You should probably add your websites to GSC.
https://search.google.com/search-console
And yes, you probably should, if only to pre-register your ownership thereof if google ever decides to nuke you from orbit