He mentioned your equity could decrease if neighborhood changes.  

Every system you try will have flaws, or you may salivate over a feature that appears in other software.Some familiar names are mentioned frequently: Stessa, Apartments.com, RentRedi, TenantCloud, Innago, RentManager, Avail, Rentec Direct, Doorloop, etc.I recommend conducting thorough research on each app online to understand their offerings, pricing, etc.

Not sure if we can mention names specifically here in the forums so you'll want to search Google for rent collection for landlords or similar.Highly recommend having security deposit and rent hit a separate bank account from your personal. 

As others have mentioned you could have a conversation with your tenant(s) about splitting the cost.

(Still awaiting Seller to confirm report it’s been done as she agreed to the inspectors recommendation but has mentioned she’s not replacing it) In additional to the foundation has shifted and need reconstructed due to a lot of slopping in the home (My agent said it comes with wear and tear, so they might argue that their not going to fix it so I didn’t put it on the IRSA to repair).

This deal that you mentioned sounds at first blush that it's dead in the water because of the large deposit.

I think the non-refundable fee is low based on the damage pets can do (not to mention tenants).

Property manager had pest control come and they mentioned “partial exclusion” on an invoice, and calling the pest company I found records that they sealed up those drains.

The books mentioned above are a great place to start!

As @Chris Seveney mentioned there is not really enough equity in house 3 to get a meaningful LOC. even if you were able to leverage enough to pay off House 2 the new rate you would be paying would be higher than the existing mortgage, so you would still be behind overall.Your ROI on those payoffs vs keeping money in index funds is not very good either.Lastly, remember that cash flow from rentals can seem good until it’s not.