I told them in the lease it states you will forfeit last month rent and security deposit if you move out early, right away there was this other guy there with her and right away he started to accuse me of fraud by "claiming" I had her sign a different lease then what I have.

I didn't even consider a fake slip and fall or other false accusation possibility.  

IE I have a partner that will buy it when in fact you don't and your hoping to flip it to someone you probably have never met.. so you start the transaction off with a fib.. and its hard to come back when your put on the spot.. some folks are born ********ters and can work right through that no problem because they could careless what the seller thinks.. others would be sensitive to this as I think you are and have learned... best to be straight up I would have a written doc outlining your process that they sign.. so there is no confusion and you don't get accused of being a pimp.

My concern is that if we rent it out while we are away (which would begin as soon as we purchase the property) that we could be accused of using it as a rental property when we agreed upon it being a primary residence.  

Of course, it's not nice to discriminate and I don't recommend it, but you don't have to worry about being falsely accused as much as other landlords do.My best advice for tenant screening is to use the credit report to make sure they told the truth on the application about previous addresses.  

I am still going to have the WOP done since he has left a few things in the house and I don't want to have him  come back and accuse me of taking his things.

*Before I get accused of 'analysis paralysis,' we are actively saving capital to begin securely and this question is just to let me take actionable steps in the mean time.

At any rate, I don't want to be accused of fraud or "trying to hide ownership" in the event something changes. 

Chances are, you could be totally good in every aspect but that doesn't mean someone isn't going to accuse you or say otherwise.My opinion and based only on my own experience, the game changes if the homeowner is in default.

It will protect you from accusations that you are treating tenant A different from tenant B who may fall under a protected class.