This may sound a bit strange because I am a real estate broker as well, and I do enjoy getting paid my commissions, but your best bet is to deploy some type of marketing to attract the motivated sellers for the types of properties you'd like to purchase

Low occupancy is my focus (i.e. if i buy a SFR for airbnb in Atlanta, where is my best bet?)

If it was medical and most actually are medical, then when the bankruptcy is discharged, they can't file again for 7 or 8 years so they are now a pretty safe bet.

Once i get a list of targeted property owners names, physical and site addresses etc... what would be a good service to use  where I can upload my list and have all my postcard sent out with a schedule for recurring mail?

I bet they both will cover most of what you really need.  

Best bet with Trenton is tbh- Section 8 tenants at least the money is a little bit better- TBH somebody always needs a place to live and I look at it as someone is always going to get paid for it - Most landlords in Trenton I know are holding the property until the value is goes up - If it really becomes too much look into property management companies, also with the criminal vs. bad credit (I  know its lesser of 2 evils ) maybe have tenants with bad credit submit a letter of explanation maybe it can help weed out even more potential bad tenants -

I have not done this, but I bet you was the landlord insurance to cover you for the homeowner/landlord piece... and then they for sure want renters insurance but I would think that may be a bit redundant for you to obtain as well.

Vanguard) may be your best bet. 

Best bet for you would be to save up enough cash for the down payment of an apartment building as a commercial loan on an apartment building would probably be doable.

Even if you're in it for the short term, in today's rising rate environment, the 30 year option is your best bet.