Since you use it for your business, do you find there are sufficient people to search for given what you are looking to have done?

There is something about paying more taxes when you sell with a S-Corp or C-Corp  Here is a good tool to help you figure it out http://www.mycorporation.com/entity-choice-wizard/...

In general I would suggest making the choice between [ LLC+CommercialMortgages ] or [ Person + ResidentialMortgages + UmbrellaInsurancePolicy ] one time, and sticking to it.

A lease or an option  won't protect your money.A purchase contract to close within a year can be used and you can have sufficient assurances under the contract, having lien rights for improvements made. 

As it pertains to me, just starting out, I was looking at starting an LLC for a few reasons but the further I dig into it, I'm not sure it's the right choice.  

I also think 500/yr budgeted for repairs is not sufficient.  

If they pass screening and you have no other choices make sure you only have them on a M2M lease.

So many choices: 1031 into units, JV with a developer on a build project, buy three other SFRs at around $250,000 each getting close to the 1% rule.  

Not by choice either, id have to pay a ton out of pocket to sell it.

I invest for cash flow not appreciation and you don't have to be a millionaire to quit your day job if your cash flow is sufficient.