150+ websites audited and optimized for rankings in search engines in Canada and the U.S.. 50+ clients coached to implement SEO strategies across a number of verticals.
Hey! I help companies through SEO migrations like rebranding (moving to a new domain) and changing content location within an existing domain or sub-domain. The short answer is: yes, there will be a drop in rankings at the point of migration, but if everything is done properly, the ranking for pages on the new domain go back to where they were on the old one. The longer answer (with details and estimates) depends on a few things: 1) are you moving the entire domain or just a few pages? 2) how large is the site? 3) how authoritative is your old domain / new domain (age, existing external links)? 4) what's the niche of your site? Etc. Feel free to book a call if you'd like to discuss the details.
I've been working with web designers and developers to help with SEO for over decade now. Your question is common.
The short answer is... Google treats sub-domains as separate sites. So, if you go with a sub-domain for each trainer it will be like a fresh new site with no authority, which is not very good for the trainers. Nor will it bring authority to the root domain because these are fresh sites. Having trainers as sub-domains will be the same as having them on a separate domain.
My recommendation is to keep your trainer profiles as sub-directories if it's at all possible.
I hope this is still relevant and the above input helps a little. Feel free to book a call if you need to discuss more this or other cases.
I do quite a bit of site migrations (rebranding, domain changes, redesigns). Usually the goal is to preserve (and improve) organic traffic as well as preserve page authority of old pages (and transfer it to new pages).
I see that your case is different because your two sites are not related. And your first site hasn't had a chance to aggregate links (authority) yet.
The short answer is that your current situation should not affect SEO of the new site. "404 or 410 Status Codes Will Not Impact a Website’s Rankings: If Google identifies 404 or 410 pages on a site, it will continue to crawl these pages in case anything changes, but will begin to phase out the crawling frequency to concentrate more on the pages which return 200 status codes." Source: https://www.deepcrawl.com/knowledge/hangout-library/4xx-errors/
However, here's few things you can try to simplify Google's life in understanding your site:
1. Verify your domain with Google Search Console (GSC)
2. Create and XML sitemap and submit in GSC
Although "site:" is a good quick lookup option, Google suggests to use Coverage report in GSC to get more precise and reliable information on the state of your page indexing. Keep an eye on that report and don't stress too much about 404s in SERPs. They'll get removed eventually. It might take up to 12 months for Google to remove those completely but in most cases it happens much faster.
I hope it helps. Feel free to book a call if you have more questions.