You can actually increase your underground water table, but that is a whole post on how dry areas can make their own water. 

You could tap the $400k of equity in your primary, but that's a slippery slope with the little financial discipline you appear to have and could quickly lead to bankruptcy.

Since you already have an offer, it’s not really about whether the property will sit for six months, it’s about whether keeping it makes financial sense.

Make sure you have financial reserves for repairs/maintenance/CapEx I would personally sell the SFRs - slow market right now, keep that in mind with your selling price expectations.

Any impending Insurance coverage or increases?

What this usually leads to is higher rates and lots of points, which increase the amount of cash needed up front.

Unless you suddenly become a stellar STR Host and property (requiring additional spending), why not sell and make some better financial decisions....

Many experienced mentors in this group can help guide you in the right direction.I highly recommend saving as much as possible and setting aside a hedge fund for financial security.

Low down payment, but you would be increasing the value of the property with your own cash.

If the prospects look financially shaky or sketchy, I ask for the name of a co-signer - and collect payment for a background check on them.Verbally, I also ask when they are interested in taking occupancy, and I tell them the application will be made part of the lease agreement - that I can evict them if they've lied in their application.