I have the same situation, Bank owned, auction.com advertised as vacant,  will close soon.

Any good resources for figuring out what rent "should be " for my potential investment vs what tenant is currently paying or what the advertisement says?

The contractors you want don't have very professional advertising, but they all have to come to the watering hole in the morning and pick up their materials for the day.

Become as smart as you can about (1) real estate, of course, and (2) marketing (paid advertising, online and off)."

I would probably do some self-advertisement on sites like Craigslist and Facebook groups and also consider renting it to cover all or most of your mortgage until it sells

just because you are an agent doesn't make you an good investor.investor friendly agent like me are around :)i find we tend not to advertise we are..... here is why, in my opinion....I got my license bc I COULDN'T find an agent like me.I've have my license for a few yrs now. mostly to facilitate my own deal. and help other investors along the waythere are just different kinds of agents. just like there are different kinds of doctors.if you need surgery you don't go to your gp. you go to your surgeon.unfortunately agents aren't labeled unless they market themselves. luxury, REO, relocation.investor friendly agent I found go by WORD OF MOUTH. 

I recently got stung with a vacation rental as I accepted paypal for the payment.I had a vacation rental which I advertised on various online platforms, including the vacation rental section of craigslist.

Transient accommodation uses means a building containing one or more transient accommodation units, one or more of which is occupied by one or more persons, or offered or advertised as being available for such occupancy, when the right of occupancy is for a term less than monthly, such right of occupancy being available more than three (3) times in any consecutive 365-day period.

I would recommend looking for properties FSBO, I have used Craigslist before and ask if the seller would consider owner financing whether or not it is advertised.

hicould I advertise listings of other brokerages such as hud government homes and get paid if I find had buyer?