In this case, it helped me determine that #2 keep the house nice and clean, but also reveal that they lied on the application.

I suggest you listen to all the podcasts, starting with mine (LOL):http://Biggerpockets.com/show65I reveal there how I acquired a 100+ unit apartment complex worth $6M with only $5,000 out of pocket.

Each step you take reveals a new horizon.

It makes sense to me to prioritize that and see what it reveals about the area of concern and then move into the addition/repair phase informed about the situation and fix(s).  

The inspection revealed the following other issues of concern: all appliances in both units should be replaced (not immediately or urgently).

Seller's disclosure didn't reveal much.

Do enough of this analysis and the right answer for you should reveal itself.Hope some of this helps. 

Each step you take reveals a new horizon.

Some of their titles may reveal that they are solely a wholesaler versus a real estate investor.

If the leases are strong and the tenants are stable, it might be nice to keep them.On the other hand, if the tenants are an issue, there is a chance that the current owner wouldn't reveal to you the full extent of the issue.If you're a brand new investor, it could be hard to select a quality tenant unless you adequately prepare yourself for the task.Are there any more details available, or are you flying dark?