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

So this might also complicate matters significantly as I would probably need to add both an additional well and an additional septic in order to truly split these into two separate properties. 

Here's an article with additional FAQs on cost segregation studies that you may find helpful.

Also, other than RICE insurance, do you pick up any additional liability insurance in case something goes south with the deal and there is a liability issue?

One of them is the addition of another aggregator, which solved one of my connections.

Ah yes, great addition!

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?

Given appreciation is typically where you are making most of your return in any real estate, having this additional appreciation helps create much higher returns.Additionally, my single family tenants, typically stay a couple years longer than my duplex tenants.  

But this comes with additional requirements you must achieve (look up REPS). 

I have a good agent I've worked with for years and letting him represent me not only gives me the advantage of additional counsel, it also gives me someone else to do the heavy lifting so I can concentrate on the deals themselves rather than the intricacies of the actual contract, the process of moving everything through closing and all the hiccups that often come with investment properties.