Appreciation Potential:Evaluate potential appreciation in different markets by studying: Historical Market Trends: Tools like Zillow, Redfin, or local MLS can give you historical price data.

Recently, PM suddenly told me that this property needs "lead testing".My PM is not aware of this I already have 2-year lead certificate from the previous onwer AND assigned an inspector for lead inspection for me.

It sounds like you are mashing a lot of different things together here.It does not matter at all if you have an LLC, or if you, or your wife is the owner - it doesn't change any of the tax positioning in the slightest.The test to be a qualified Real Estate Professional is at least 750 hours in real property trades or businesses AND  over 50% of your professional time. 

I generally agree that homes in Cleveland should be tested for lead.

Turns out there were other posts in that thread which also tested positive for AI...

I got a feeling that life as a Private-$ Investor may be a great place to start, and these properties lend a perfect means to testing that out, solving 2 issues in 1 action, because you can JV your way out of the operational side of things AND retain that long term financial upside. 

I'd look for signs of arcing around those outlets.Other things I look for are how is the foundation, cracks in the walls (assuming lath and plaster), condition of the mechanicals, depending on what the house is built on, I may get a radon test done for the air and water (near me there is a lot of ledge, so radon is an issue in most homes). 

See below example deal and associated data points.Happy to share a copy!

That said, do ask yourself before signing on the bottom line: if this tax strategy fails the IRS scrutiny test - what happens then?

You can get the STR data from something like AirDNA and then check out what your competitors offer on sites like Airbnb/VRBO.Negotiations will also depend on their cash flow and how much of the business you buy.