Hundreds of Subdomains under a powerful domain

[thinkingdif]

Hello,

I own a domain FeedsPortal - com

As you can see from the link profile, it has some fantastic referring domains and links. Because of this, it has a DA of 86, with a good CF/TF.

The problem is that nearly all of these powerful links are for the sub domains under the main domain.

For example, it has a link on this page on MSN...

https://www.msn.com/en-us/news/offbeat/finland-home-of-the-dollar103000-speeding-ticket/ar-AA9GA9i?ocid=ansAtlantic11

On this MSN article, it has a link to http://feedproxy.google.com/~r/TheAtlantic/~3/PK4bw0Tkkps/story01.htm (a link under Google.com), which then forwards to my domain under a sub domain http://theatlantic.feedsportal.com/c/34375/f/.....

I have many hundreds of sub domains like this.

I have a feeling redirecting all non-existent sub domains to the homepage would be a bad idea for SEO.

Does anyone else see of a way to do this without harming my SEO?

I suppose the only way to do it properly would be to write articles about each subdomain. For example, http://theatlantic.feedsportal.com, write an article about The Atlantic, then forward all traffic meant for theatlantic.feedsportal.com to feedsportal.com/10-reasons-why-the-atlantic-is-great/

Does anyone else have an idea of how to at least get a list of the non-existant sub domains that have links so I can maybe create articles for each sub domain? Or is there a simpler way to do this.

Thanks!