Great property, perfect setup for a duplex with separate driveways, entrances, back patios w/ storage, brand new roof, plumbing, newer HVAC, appliances, flooring, etc.

If I were to rent for 6 moths, the lease would end Feb/March time frame given its almost September now. 

How long (potentially) could it set us back on buying our own home if we did the investment first.  

Final appraisal came in way higher than we expected and made $57,000 after paying ourselves back and hard-money lender.

It's beneficial to you that their lease is about to come to an end.

When you do this you end up with two properties leveraged. 

I have no record of this installation, nor does the property manager, or the roofing company.To get the roof back under warranty, I need to pay 3000$ to remove the screens.I know that I have no record of this installation.

You state that everything is equal but are concerned that not everything is equal...It's very possible to see a price spread like that even with comparable coverage but it's also vitally important you work with someone that has your back to make sure you understand your coverage before you'd have to use it.  

If you want to do some flips or BRRRRs then you could consider taking out a Line of Credit against the three properties so you can use the cash with interest only payments for a short term project and then pay it back and then use it again (Lines of Credit are revolving - meaning you get to keep using the money).

Listen to as many of the various BP podcasts that you can, go back and listen to some older ones as well.