Social APP-API ID

Hi there,
I completely redesigned my crowdfunding website jointlyup.de from the beginning, i.e. I took the existing one off the net and started from the beginning with a blanco wordpress, then installed the current fundingpress theme and redesigned the site. That means all Social APP ID, Secret and so on are not on the current site. Now my question, should I register the jointlyup.de site via Google, Facebook and co or can I transfer the codes from the old jointlyup.de into the new jointlyup.de. The new site with a different structure (images, page names, etc.) is recognized. If the codes are recognized or were connected to the social sites (Facebook and co) when the codes were created. What can or should I do? I have no experience in that. Create new or copy old codes into the new site, the domain has not changed.
The same applies to the API-ID. Can or should I take it from the old jointlyup or is it better to create a new one without there being a conflict for Google since at once two APIs are for the same page.

Thanks a lot for your help and Kind regards Kirano