Very unique, extremely short sale qt

Looking for help on what has to be an extremely unique deal. Please be patient and help with ideas if you can --> Present Owner bought house in '07 lived there for a couple years. House had/has black mold from plumbing leaks. Also, the full Bsmt foundation has structural cracks leading to more mold. They had industrial hygenists, structural engineers in. The short of it: they tried to fix, couldn't. Sick kids so they moved out & bought another house. Empty house for 3+/- yrs. County agreed with the bad condition & reduced the value to land value only ($30k). Had 1st & 2nd mortgages totaling over $200k. Owners filed & went thru bankruptcy. Orig mortg holder wrote it off & assigned 1st to FreddieMac. Freddie has just last month sold it to one debt collector who sold it to another who now is contacting owner and offering 'deed in lieu'. 2nd mort was assigned last month from orig holder to another lender/collector. These debts were discharged in the BK. Owner was told they are now responsible for maintenance & taxes. Taxes are delinquent but won't reach the threshold for county to pursue foreclosure for another 12 months, due to low tax value. They could wait and let it go to tax sale or offer a 'deed in lieu' to the most recent 1st mortgage holder BUT I would like to get in the middle, write an assignment contract (if possible??). The owner has someone that says they want to buy it/tear down build new. Rehabber would pay a little more and do the major rehab work.
Told you it was unique.... Help!! Its getting down to crunch time so ANY suggestions, caveats, experience in this type of deal? Can the recent 1st mort holder stop my assignment offer to the owner for $20k +/- so I can flip it to new builder? Then what about the 2nd holder?? I see an opportunity but don't have the cash to just buy it. Thanks for reading and responding.