@Colin12 just a H1 will not make your page rank without additional content.

I love doing everything as it should. so: just add a correct H1 to the page.

you could always search in Google and compare the ranking of the page. If the same url's get there in the same order = no difference. If there is a difference you could consider using some variation on your site.

Most easy: use what you consider to be right en build great content. Google will find this very small difference out.

@Colin12 Do not know where you get errors? Search console?

A H1 is a nice best practice, but it will not save you on pages with limited content.
Consider to take away all headings in the boiler plate content (After "Stay In Touch")

@JCN-SBWD cool! (from a SEO perspective) I would speculate that Google considers this related keywords to the keywords optimized for, and thus ranks for it.
Other option would be that you have incoming links with that keyword. I looked and did not see much of that kind.

You could take the "copyright" keyword off the page for a while and see if it changes. But that would take some time as Google will consider your page relevant to it for at least a while (Sorry)

The latest insights are that Google will discard most sidewide links. The time of Google delivering penalties for this kind of behavior is behind us.

So unless you have terrible rankings and or warnings in Search console let it be.

Best practice for the future is to limit the amount of sidewide links to the necessary ones. Also it looks a bit spammy for the clients. "design by Company" is enough, if at all.

I would only buy it in order to actually rank with that specific content on Wikipedia or the others. So: Just as you could rank with an article on linkedin that is pickedup by Google.

This would only be helpful and sustain longer period of time if it actually is great content, and they do have a solid reason to link to you. And the visitors have a solid reason to want to know more. The link to your website will NOT have link value to your website as far as google is concerned. They are nofollow links.

A company could also decide to get a wikipedia page in order to educate. To give an in dept article about something relevant that you have a benefit from it's adoption. Like bluetooth, wifi 6, gluten free beer.

You would only do it in order to get the few clicks on that link that is on that page or follow up searches..

For example: https://en.wikipedia.org/wiki/The_Coca-Cola_Company is a great page that could result in actual traffic.

Google has an extremely long memory for old URL's being live and linking. It is anoying realy.

Links from websites to your old domain are still there, you want to hold on to that value. Thus you will keep the old domain redirected. You do not need a server for that, just the domain pointing to the server and redirecting it on your server. Your web hosting support can help you with that (if not, switch to wp engine)

please do create a HTML sitemap in order to facilitate google crawling all of your pages and helping your visitors finding specific pages.