I drafted a lease agreement using other agreements and looked up some things from the Ohio revised code.

This is a common issue, but having stricter cost control measures or a contingency buffer in place could help on future projects.

My 2 cents, Save more for the downpayment, closing costs and reserves.

I’m considering hiring a lawyer to try and recover the cost of the repairs and potentially my extended holding costs.

She signed a purchase contract for $75K with closing within 30 days.  

https://www.biggerpockets.com/blog/what-documents-do-you-nee...BRRRR Loans: What Are the Options, and How Do DSCR Loans Stack Up?

We pay them back at close.For people/teams that do something similar, I'm curious what software you use or spreadsheets you've created to: Track cash current cash flow and projected cash flow for the whole business that including fixed costs like payroll and variable costs as well.

(Approach - 2) - He says that if he is asked to pull permits, he is not responsible for any additional work that the inspector may throw (basically more money out of my pocket on the rehab costs).

Since you cannot predict what things may cost 10 years from now, its not really useful in my opinion to get too detailed trying to analyze the way you have here.

A key takeaway from this project was the importance of budgeting for unexpected renovation costs.