Do I use the "Residential Lease Amendment" to note the increase in rent?

Also, since a cost segregation study increases your cash flow, you can reinvest that cash flow into your property to make improvements which therefore increases the value.Improve Liquidity for Estate PlanningThe accelerated depreciation created through a cost segregation study reduces your taxable income which means you are paying less in taxes and get to keep more cash in the bank.

In the end we are able to attract high quality tenants and higher rents.

If you are talking about refinancing to stretch your payments out over a longer time, that is also an way to increase cashflow. 

Now is one of the best times to get into the market, once the Fed starts lowering rates that's going to bring more demand into the marketplace causing prices to increase at a faster pace again so if you get in now you capture that growth and get the opportunity to refi when rates are more favorable in a year or two.

The types of tenants they attract will not take good care of high end finishes.

Securing 2nd position financing is difficult, and increasingly so when the property is already levered at 70% LTV as your example. 

I assume a new HVAC will increase appraisal?

You just have to increase the equity enough that the new loan will cover your previous acquisition cost+ expenses.so you can get all or most of your money back out to go do it again.

There are many variables that affect closings on condos here in Miami-Dade County, such as condo riders, anticipated insurance premium increases, etc.