If the stairs need replacing did you give the PM that directive to get estimates and have them replaced and what did they do? 

I calculated rent estimates using both BP rental tool and Rentometer.com so the larger side will rent for average $550/month per room. 

The rehab + landscaping = $65K (approximately) Would it be better to seek out private money and pay them back at refi or attempt a cash out refi.

It does not apply to 1- or 2-unit properties.Income Calculation: To conduct the test, FHA requires that the estimated rental income from all units, including the one in which the borrower will reside (if the borrower is not occupying the unit as their primary residence), be calculated.

If a property meets the 1% rule, it typically indicates that it can cover its mortgage and other expenses while still providing positive cash flow.35% Operational Expenses: This rule helps estimate the proportion of rental income that will be consumed by operating expenses, excluding the mortgage.

While we lean heavily on the pro's  for repairs and estimates it makes it much easier when we know the typical issues and concerns on the plumbing, roof, electrical etc sides of a property. 

For example, after running comparables, I found that a property's estimated value is $580,000.00, and they have an existing mortgage of $420,000.

Great to see you putting the BP calc to work.Did you get an actual quote for insurance or is this an online estimate?

What are good strategies or online calculators to help make rehab estimates? 

It would also be wise to have a reputable roofing contractor who has been in business for several years walk the roof and give you an estimate.