Hello Murray, Assuming the new owners are interested in selling, you'd want to offer enough to help them cover their transfer taxes, legal/title fees, other closing costs, and possibly their moving costs. 

Most conventional or Non-QM lenders will require an independent third part assessment but if the LTV is low enough and some compensating factors, occasionally for a rate and term refinance lenders will allow a drive by or 'online' appraisal.

Lenders often have 'in house' capital to lend that can be accessed via exception or compensating factors.

Its a fee for tax planning and financial advise. 

Alternatively, a fixed monthly fee based on estimated usage or dividing the bill by square footage occupied could simplify matters, though fairness might vary.

For removing the items, do gas and dump fees. 

Regarding the risk factor you mention, tenants not paying.

This is a larger 2500sqft home so that makes a lot of sense.I'm sure the age of the home is a factor in the replacement value as well. 

@Alexander Merritt There is also something to investing that I've dubbed the "headache factor."  

When targeting markets for investments under $250k, there are several factors to consider, including affordability, rental demand, economic growth, and potential for appreciation.