I see all kinds of warning signs and I think others here do too.

Several agents warned me about getting my license because, in their experience, sellers were skeptical of investor agents.  

In some areas, three blocks makes a tremendous difference, which is also fair warning against overly optimistic valuations of comps.

There is also extensive drywall damage (including some visible mold in one small area) due to roof leaks, some which my inspector feels are active leaks, and a septic water level warning light.I was told by the management company that an OO doesn't have an inspection period (not true) and that HUD will never do any repairs (per their handbook they can repair major--roof, electrical, plumbing, structural, septic--issues at their discretion if previously undisclosed but uncovered by OO's professional inspector and reported to HUD within 15 days, don't know about in practice). 

I am kicking myself enough already and will undoubtedly lose a substantial amount on this project.Bill Norris - AB RenovationsDon't say I didn't warn you, folks.  

Any general warnings/things to look out for if bidding (i.e. lien issues, scams, etc)?

Great advice Mike, also a great warning for a lot of us who don't hear from our renters unless there is a leak and just see the checks every month, it is really good to schedule periodic checks on critical maintenance.

So, in my case, if the president of the bank can't answer my questions, my broker's questions, or even my attorney's questions and I'm warned by people around me that do it for a living it's a no go for me.

I send him a text every month on the 1st to pay on time or he has to pay a $50 late fee, which of course he never does, so I roll over and add the late fees to the next month and he'll eventually pay the total late fee.In the meantime, should I give him a warning and discuss with him what happened?

For the smoker make sure you give them plenty of advance warning of the change to allow you enough time to find a replacement tenant.Hopefully they will decide to leave because if they stay they will not stop smoking and you will likely end up having to evict.