IFTTT is removing that service:https://help.ifttt.com/hc/en-us/articles/360024449693-Important-update-about-Classifieds

It's not about what can classify as a millionaire on paper.

What does it matter what they classify some part of the job as?

For example, look at auto deal association trade publications, they often have classifieds with dealerships for sale, paint shops and body shops for sale or lease and those seeking opportunities.

I think most people classify private money as hard money.How are you thinking of them differently?

First, decide what type of lead that you want to find_(type of buyer) and/or (motivated seller).Next, "Google" free classified ads or free classifieds along with your target city.

So, is there a set of rules to classify apartments or for the most part the beauty is in the eye of the beholder?

You may not want to wait the 4-5+ years for the market to get you to where you want to be.To tie my point in, people tend not to over pay in the investor market. 4plexs are classified as residential properties and have to be evaluated as such using the comparable approach  it is what it is. 

Specifically, I'm asking about multi-member LLCs that are classified as a partnership.

It is quite possible that with 3-4 rooms, your house is not classified as a rooming house - check your community's bylaws with respect to the number of unrelated adults living in a residence.If you are planning to convert additional houses into rooming houses, verify that a rooming/boarding house is permitted under present zoning before you acquire the property.