I think purchasing a primary conservatively with a lower down payment (to leave enough for the required larger down payment on an investment) would be my suggestion, if you purchase your primary home first. 

Then I want to move my stuff over to the inherited tenants side (as it’s the nicer unit).Unfortunately the inherited tenants have 4 larger dogs, a guinea pig, and two cats (one of which they adopted a week before closing).

The house square footage is also a bit larger than the others in the neighborhood.

But assuming you come to a good value for you, you could likely increase that dollar amount for the same net cost to you long term if he will hold a note at low or no interest avoiding larger bank loans.

It's not so hard to buy a larger property.

If you can't afford the required down payment and closing costs how are you going to afford any sort of repair, maintenance, vacancy or other unanticipated financial shortfall? 

If it's a larger organization, feel free to inquire about their different staff qualifications.2.

BP is having some sort of issue. 

Did you get a promotion where your job has you traveling 50% of the time leaving you unable to take care of the larger house?

Another option is to invest somewhere that family or friends live and pay them to be a sort of “project manager” while the property gets rent ready.