Ask how they intend to pay for a year or two of rent.I ask for a statement of assets and discuss any red flags or ambiguities with them.

@Chris Blackburn, while I can't speak to this specifically, there are a few red flags I see in your post.1: A Realtor has to be a member of the national association of realtors, an industry trade group primarily focused on your typical home buyer.  

And when a property cycles back to the market, it's not always a red flag – sometimes it's just market dynamics at work.

Is this a red flag, or could it just mean there’s an untapped market here?

Are there any red flags or challenges specific to this neighborhood that I should keep in mind?

I have just received the same callThis a legitimate business model for a STR company, but the website raised a lot of red flags and I would not feel comfortable doing business with them.

I just bought all the drywall, cement board, and a 3/4 full thing of red guard water proofing that I need for my entire bathroom remodel for no joke $110, that would have cost me $400+ at the store but someone else who already finished their bathroom just had a ton left over.

However neither person is local , they both have filled out applications and seem to check out , but both have "Not for Real ID" IDs which seems like a red flag to me. 

The fact that you've "put over 5 offers on houses since February" and moved to a different strategy is a huge red flag for me.

I then look at area vacancies, economic conditions, employment opportunities, area demographics and verify that the property has not been red tagged or have any other underlying problems that might make it difficult to resell or rent.When I have my financial information then I can consider debt service and costs related to equity partners in the overall income produced.