To whom is the seller attempting to pass accountability for this deferred maintenance?

See your attorney.While many may think trying to simply cover the buying/borrowing side, the terms can back fire on you later on as a borrower, you might not be dealing with that original lender, so think ahead and long term before going more than 10 years.

I simply am looking to build my network of fellow real estate professionals,

Simply put you will need to buy the home from her as-is all cash or private money, make your repairs and then sell for profit. 

Once I have an idea I would determine the cost to replace and simply divide by the remaining life expectancy to give amount needed to save by year or month.  

Not sure I would want to evict everyone at the same time, simply due to the fact that tenants could talk and get very frustrated that everyone is getting tossed out.  

Are the expenses (potential cleaning, bills, service calls, etc.) simply subtracted from the collected rent?

First off cash on cash is simply, how much money, your money makes every year.

Both are fully empty.Both need some work before renting out, nothing big it appears right now, but definitely paint/floor work and some restructuring of how the units fit together.Should we offer individually or attempt to get them in a package deal?

When we bought our 14 unit building a couple years ago, we just simply raised the rents.