What kind of deal should I work out if I approach this through a partnership with a friend/colleague? 

I've pitched this all to my investor friend with a general "I'll eat what I kill" approach so as to align our interest and not be a drag on things.

I take the crawl, walk run approach.  

I liked the straightforward approach and collegiality.

I'm not a lawyer but my gut tells me that you might even run into legality issues with this approach.  

Or, give me your idea on a better approach. 

He approached me about buying him out but I don't have the kind of capital to buy the entire lot right away but could buy several lots over time which he is fine with.

After I got of the phone with the seller, I did some more research on the property and found out the bank has recently filed another Lis Pendens in January on top of being two years behind on the property taxes.How should I approach the seller and this deal?

An appraiser (MAI) can tell you what the CAP rate should be on office buildings in your area, from that together with lease amounts you can get a value as to the income approach.

We are fast approaching the 30 day mark and I am very nervous.