Once bid is accepted you should have a purchase contract between you and the note seller. 

I am under contract at $125k for duplex that currently gets $1750 per month gross rent.

I just got one of my clients a duplex under contract and in the process was able to connect with the listing agent.

I always assume electricity, gas, water, sewage, trash, snow/lawn care, and wifi to be paid by tenant (except HOA). 

Do the tenants pay for 100% of water/sewer/electric/gas/trash?

Sure, you could argue that you'd be collecting rent from your tenants, but good luck finding a multi that has enough positive cash flow to cover the entire mortgage, taxes, insurance, vacancy, maintenance, capex and your living expenses, food, gas, utilities, etc.

I'm under contract to purchase some smaller multi's in rapidly changing neighborhoods.   

I do want it to actually look good ;)Well guys, I was going to go back and look at it on Sunday afternoon and it went under contract Sunday morning. 

In the last 10yrs there was a person/investor that has an installment contract for deed on the property, they stopped paying their payments, and also collected security deposits from the tenants.

That is not always but if we just look back to last recession and check prices in the oil and gas regions ($100 barrel)  one might see these locales were not affected as much or not at all as I recall.