Okay, working with a large site that, for business reasons beyond organic search, wants to split an existing site in two. So, the old domain name stays and a new one is born with some of the content from the old site, along with some new content of its own.
The general idea, for more than just search reasons, is that it makes both the old site and new sites more purely about their respective subject matter. The existing content on the old site that is becoming part of the new site will be 301'd to the new site's domain. So, the old site will have a lot of 301s and links to the new site. No links coming back from the new site to the old site anticipated at this time.
Would like any and all insights into any potential pitfalls and best practices for this to come off as well as it can under the circumstances.
For instance, should all those links from the old site to the new site be nofollowed, kind of like a non-editorial link to an affiliate or advertiser? Is there weirdness for Google in 301ing to a new domain from some, but not all, content of the old site. Would you individually submit requests to remove from index for the hundreds and hundreds of old site pages moving to the new site or just figure that the 301 will eventually take care of that? Is there substantial organic search risk of any kind to the old site, beyond the obvious of just not having those pages to produce any more? Anything else? Any ideas about how long the new site can expect to wander the wilderness of no organic search traffic? The old site has a 45 domain authority.
Thanks!