I have a basic one, but am looking for something more robust for both smaller project (duplex) as well as a apartment building 

also can i go to court to collect unpaid rent for that month?

I personally think vacancy at 5% is too low; it basically means the property is only empty once every 24 months.

Basically would above deal be doable and how much would it cost?

"Consideration" is important... there are basics to any agreement in US.

if you're gonna pay them something have an attorney write up a formal "release"it will say that you are not admitting fault and they can never hold you responsible again for these problems or any other problems related to this property.negotiate them down as much as possible because if you messed up at all on the sellers disclosure you could get hammered, and nobody wants to go to court over a few bucks anyway.the release will protect you against any future claims!

The fact they are complaining online might be an indication the property manager dealt with them properly so be sure to ask the manager for their side of the story.I hope this basic guide helps.

Basically someone I can offload parts of this project to in lieu of DIYing. 

I use the 50% as a guideline only...basically a sanity check on the more detailed numbers. 

Any feedback and insight would be greatly appreciated :)  The crash of 2008 was basically 5 markets.