What would you do from here, pay them off sooner to increase the cash flow, or keep leveraging? 

It establishes a base that's $40 lower, which all future rent increases are based on. 

It's a site that is increasingly becoming more obsolete as each day passes.

Increasing job growth and a strong economy brings an ideal investment in these markets.

We plan to remove them all to protect from tax increases on our current primary, but I am afraid that now that the other properties won't have homesteads, we may see skyrocketing tax bills and it will eat into already small cash flow from rental income.Does anyone have advice for how to handle this situation other than just increasing rent?

They may also require US credit history, although there are a handful that will not require a US credit report for an increased rate/ reduction in LTV. 

The biggest thing to me is buying in quality areas that will increase in value over time.

I will mention that a hot tub could really increase the frequency of bookings. 

By adding the 3rd bedrooms, we were confident that it would increase rents and our valuation considerably.

Also, the tax benefits of the buy and holds help offset the increased tax consequences of fix and flips.