If you have the right systems and people in place to facilitate due diligence on a property independent of the seller/owner or broker representing the seller,  then no, you should not care if an agency that owns & purchases rentals is also selling properties. 

If you think people don’t want to move during winter how will you find any tenants if yours moves out?  

It's usually not worth it to bid because the clueless people are driving the prices up. 

However, I'm a bit confused about the process, specifically:Who is responsible for paying the closing costs, and how do you bring it up?

I like turnkey for people who want to invest, but don't want to build a team.

Whenever you get a recommendation, always check them out online especially if you don't know the people recommending them. 

your better bet is probably to try and bring on an equity partner into the deal. have you considered that?

Once repaired it would bring around $900 per house each month.

Landlords always think the worst (and it can be true), but sometimes people go to the hospital, die, or have things to deal with.What has your relationship been like to-date?

Most people would prefer to not have to drag their RV or Boat back "into" town, especially if it is on the way to their primary rec area.