I copied info from the Census and then combined the Bigger Pockets recommendations for what you should look for in a market as well as their recommended %'s which can be found in notes if you hover over the little triangle mark in the cell.

Next if you can find a Rent to Own (always a seller finance) and confirm with the current owner that you could sublease it, then you put 3.5% down to the owner and have a monthly payment which you would need to get more than to cover PITI,capex,mgmt.Finding a small portfolio lender / credit union who would maybe let you refinance your current lease and combine into one larger loan using your own home as collateral.

It has a good combination of cash flow coupled with strong economic and demographic fundamentals and a vibrant, diverse economy.

I combined about 3 blogs or posts I have done on the subject. 

But yes, in general there's ways to combine multiple 1031s from multiple entities into the same replacement properties.

Instead of replacing these two units, should I just combine it (per se) and get a High Efficiency Heat pump?

On balance the combination of these two changes adds $10,000 - $15,000 in purchasing power to a Buyer in my markets purchasing a property at the median price.Low interest rates drive asset prices upwards. 

The number of units on there is way more than actual number of units that the building currently has, so I assume the current owner has combined some of the units (but most likely without a written consent). 

The rental square footage at 100% and then a portion of the share squared footage all get combined into a ratio for deduction a portion of the other expenses (mortagge, tax, insurance, utilites)When you sell your 121 will not be 50% excluded. 

The discipline of the Marines, with a college degree in finance, a real estate license, and a desire to learn might just be the perfect combination.