and/or reduce expenses (can you bill back the utilities to the tenants?)

I recommend a home inspector so you can get a 4-Point Inspection and possibly a Wind Mit Certificate - which determine whether the house is insurable and if so, can reduce the cost of insurance.  

Example:Duplex purchased for $100,00020% down payment would be $20,000Seller agrees to provide a seller credit of $10,000Your loan amount becomes $110,000 while you down payment reduces to $10,000A conventional loan only allows you to do 2% (maybe 3%) seller credit of the agreed upon price; whereas a commercial loan does not have that restriction.

I offered to purchase a portable unit for her to use and reduce rent to help pay for the cost of electricity for the summer months (~$50 a month), which she initially agreed to.

They keep their license active, reduce their fees, and earn referral fees. 

Would I be able to collect a reduced commission when my only role in a transaction is lead generation?

The payment on the HELOC reduces the cash on cash returns but the way I look at it is some money is better than no money. 

I would have to sell one of my two properties to reduce my living expenses and that is not what I wanted to do today.

The home should be listed for fair market value and will more than likely sell fair market value, all things being equal.If you can't convince the bank to reduce their recovery by reducing their net proceeds so you can make a profit, i'd move on to the next deal.

No good reason to reduce your cash position and pay higher rates at this point.