Additionally, is it reasonable to request the current leases and what I believe is called the rent rider form (please correct me if that's not a real thing) prior to making an offer?

Yes it’s common to have an additional guarantor who has a balance sheet added as a credit enhancement.

Additionally, checking local listings on Zillow or Craigslist can help fine-tune the rental rates in that specific area.

Also, make sure there aren't additional restrictions on the property condition, compared to a conventional loan. 

Make sure to have a security deposit that takes into account the additional risk.

At the current price, adding the additional lots would make them about $30,000 per lot, depending on the price of the additional utilities that need to be added. 

Aside from that the biggest value add areas I see are as follows: Kitchens, Bathrooms, decks/patios (if added), additional rooms/bathsKitchens and bathrooms tend to be the go-to, but all of those can help you get the most bang for your buck. just keep in mind that if the area is already of high quality, then it may not be the best area to spend the money vs something that is blaringly in need of an update.

Happy to connect and share some additional experiences if that interests you.  

What are you attempting to accomplish?

I charge fees that create additional income.