It sounds like you're in a good position to evaluate your options carefully.

IMHOThere are more international students staying, I've seen it where I work (at a university), but many of the newcomers are not students and a country our size can't handle that many people in a relatively short period of time. 

In a matter of fact I can say pretty confidently that most SFR eventually would cash flow.

As long as you paid a contractor or someone who’s not an employee $600 or more in a tax year, you are required to issue them a Form 1099, regardless of whether you paid them via cash, check, or another method.

If you have a 6 bedroom in an area that does not have a university (students looking for shared space) or is in a family friendly place it may sit vacant longer between tenants.For Capex, try not to use a generic number - look at the roof, furnace, hot water tank, kitchen - when will each need to be done and what will it cost?

Hopefully I can upgrade myself from investing in real estate to Note in a year or so.....  

However, if you know and have a relationship with the person/team that will be doing the rehab for you in your absence and trust they have your vision in mind then you are in a better place to start. 

Similarly, if you put all Class D tenants in a Class A 4-plex, what do you think will happen?

If you are living in a place that is satisfactory why not change the arrangement with the landlord?  

Quote from @Elizabeth Rose: @Josh Bowser this tip of doing a quick search on county GIS or software to see if homes in a neighborhood are owned in personal names or LLCs is gold, thank you!