Here is California, if you form an LLC the State Franchise Tax board requires an annual $800 tax simply for existing, albeit if one is in business, one can expects expenses.

Because of the medical issues the existing tenant has, he cannot live with animals and that’s the reason he is on the property.

If done right you could rent your existing SFH for enough to cover the holding costs until you meet your exit goal for the new project.

These wood shake roofs are now unlawful in the Peoples Republic of Kalifornia to install, BUT, will a lender lend on a home with an existing wood shake roof that is in servicable condition in a lower risk area, to wit, a residential area in a city (Fresno)?

*Only one of the units was vacant, so we haven't seen the bottom unit yet - one has to be open to imagining the possibilities that exist, sight unseen.  

The most dangerous situation is the landlord that owns 1 property.If you are midway between residential and commercial (5 properties) the insurance companies start considering you a risk and will only cover you with  more expensive commercial policies that require you to go to LLC's while LLC's might not be appropriate for someone getting new mortgages and has existing mortgages.What is the saying-go big or go home?

Last, is there any realignment of the lateral that would still allow you to use the existing tap but not require going under the driveway?

Why not just search for existing topics, like this one?

An existing area "is what it is".  

to help people understand and analyze these types of opportunities, as no other book / course exists that helps investors with that as far as I am aware.