I'm in a position to acquire more, but have recently run into a lot of dead-ends.

FHA is tough on a few things like "Chipped paint" any signs of chipped paint will stop financing and need to be addressed (Painted), Loose or missing hand railings, Water damage, Mold, Termites, Outdated electrical or any wiring that is exposed.FHA will also stop you dead in your tracks if the appraisal shows anything that is considered a "hazard or safety issue" and must be fixed.

Our farm animals were left with no food in the dead of winter. 

It was infested with dead rats, other rodents and unlivable by anyone's standards.

However, here is my two cents :)I have been in this exact situation (along with people fabricating their pay stubs, and even using a dead persons SSN)...

You could start by getting a soil scientist out to evaluate the land - he won't know exactly what it'll perc for without doing the test, but he will likely be able to tell you if it's a dead deal right out of the gate.  

d) set mouse traps and check them often (not a set it and forget it option and dead animals can stink, hard to check traps in a crawlspace regularly no?)

We are in Michigan and have just now come out of the winter "dead months" in the past 3 weeks or so. 

I just realized none of my properties are in route, in fact all of them are on dead end streets so anyone driving by is either lost or is there on purpose. 

The worst part was that they had a baby living in the house with them, after we bombed the place there was over 1000 dead roaches, and I found a live snake behind the hot water heater 4 feet from a mattress that was laying on the floor that someone was sleeping on.