Depending on what you want to do and what role you want to play, would depend on how you should go about it. =)

In these markets, I would be worried about crime, activity of illegal immigrants, and such. 

Ask them to confirm the license is still active.

You absolutlely need to be direct to seller or have close, personal relationships with wholesalers and active agents.

Additionally if you're running an active business in the IRA the income will have to pay UBIT.   

They didn't actively advertiseour home on websites and we had low tenantresponse.

Most agents paying for leads are inexperienced, which is why they need to pay for leads.Look for an agent with a minimum of 15 years of active experience.

As someone actively investing in STRs and looking to scale, this raises some concerns for me about the long-term viability of this strategy.I understand the tension between hotels and STRs, especially in popular tourist destinations, but I’m curious:How real is this threat?

I spent a decade in advertising, before founding and running a custom wood shop for another decade, so 'm pretty good at the self-promotion.I agree with you that the more gorilla approach would be most effective and that's actually what i've been doing – calling RE agents in my service area with active listings, introducing myself to property managers and leasing agents...To answer your question, I will have to handle the work myself for 6-12 months to build out the SOPs and field service management systems, but I have a lot of relationships for those looking to "do the work".I'll check out the meet up and would love to grab a cup of coffee, I'll shoot you an email.

The IRS generally does not allow you to deduct expenses for a property that has not been placed into service, as deductions typically apply to operational properties actively being used to produce income.