An S-corp might help to mitigate the tax, but it should be weighed against the admin considerations of compliance (eg: payroll, reasonable comp, etc.)

She pays modest pet fee per month.

@Maddison MartinSome market just don't produce cash flow, and the way to profit is through appreciation and tax benefits.

your business will have it's own tax return depending on how you structure it and you'll get a partner return either profit or loss and that will pass through to you typically if you are an LP. if you are GP it's a little different. you also get the depreciation of the asset as a tax write off as well as interest expense typically. 

A lesson learned in this process so far is that adjusting rent is important specially considering the increases in taxes when going from 4% to 6%.

Taxes are reappraised every year and if it is not your homestead, your property taxes can go up without limit.You have to really know the market and not just what prices seem to be.

I need help on how to start a system to buy and sell tax deeds.

You didn't even mention tenants who don't pay rent, evictions, vacancies, HOA violations, the consistent rise in taxes and insurance, bad property managers, and the many other issues that cut into your profit. 

Also how do you set up contracts that are in your favor, such as being able to get referral fees that are more your in your favor?

Don’t mention any sort of “program,” but if they ask, this document is it.I hope you use a CPA to do your taxes.