This strategy has paid off in SEO at the expense of having a single place and methodology for managing the sites.

I am thinking that one month of SEO will do hardly anything. 

You've done a lot of research on SEO techniques, but what have you actually implemented?

I worked for a company selling SEO services to get people information ranked higher and it was an entire team dedicated to creating the content to get the pages higher on the search engines.  

but the backend "Sites" module does not permit much control from a SEO standpoint, so I have spent a lot of time coming up with workarounds.

I thought the automation offered by VRBO and Airbnb (SEO, Listing and photos management, price management, calendar management, inquiries and in case of dispute, some support) was exactly why we were paying them, but you are right if it brings you additional revenue, then it makes sense.And yes on top of what we said above about the vrbo vs airbnb sweet spots I do see the same thing as you when you say: " My perception is that people using VRBO are middle aged people that don't mind spending money on a nice place. 

Surely all 6 red flags, like their domain being a medical site as recently as October, their own company not ranking for its own brand name, and all examples of SEO rankings achieved for clients have no PPC ads running on them among others, will all be cleared up as a big misunderstanding once we speak. :)

I hope this is a part of a broader marketing plan  which includes a SEO, which is like a garden.  

@Zachary Clough I use Upwork a lot in my free time for SMM, SEO, and web design.

Does your group do direct mail or online marketing (PPC, SEO)?