Separate bank account in a separate bank from my personal account. 

-In addition to merging (or separate from merging the properties) we plan to finish the basement of both properties into One Bedroom-One Bath apartments.

Painted exterior.It was a big project but straightforward as all the units were existing and separately metered.

There is one book for 49 states and a separate book for California. 

Realistically its going to cost you a little over 100 per month for the management fee with leasing and maintenance coordination being separate.   

It is also more work/cost to operate 3 separate units. 

seems like investors do a separate refi after the rehab is finished and the tenant is moved in.????  

You would need to file them separately since LTR and STR and taxed differently.

However, you can easily keep an eye out for either a single family home that you can create an in-law suite (whether in the basement, or converting a family room or other separate area of the house) or even a townhouse with a walkout exit that could have the bottom floor serve as an in-law suite.

The appraisal will help determine the price that the buyer will pay for the property at the end of the rent-to-own period.It's important to note that the property inspection and appraisal are separate processes, and they may be conducted by different professionals.