I am not familiar with OH laws, but you should not need to wait for new tenants, but should be able to implement the change when tenants renew their lease.

Love the business plan you're implementing on this one.  

What is possible to “automate away”, so managing deals is as easy as it can be?

I'm interested in integrating some automation into my flip houses.

There are a lot of helpful tools out there that can help you to bring a certain level of automation and transparency to this process, which is important especially when dealing with students, and parent co-signers.

According to the draft language, any existing or new STRs approved prior to the implementation date of the density restriction will be grandfathered in.

So to implement the strategy you want to look at the locations where flipping is possible. 

There are also additional ways to find additional cash flow, implement monthly pet fees (things like that).

My studies are way outside contracting into change implementation with robotics and human staff merger.

If they pass your screening process, go ahead and give them a new lease with your own changes and additions to the rules you want to implement.