Well Tex another thing you can do (and I've seen this work a number of times) is to explore with your attorney any possibility of criminal charges. Maybe something along the lines of fraud! Unfortunately, with the position it sounds like they are in threatening them with an IOU type of thing isn't going to do much, look at all the IOU's they already have against them.
In the meantime they have a place to live and trust me they will milk it for as long as they can. You may also want to explore the possibility of threatening the wifes job as a teacher, therebuy cutting of their source of comfort money. I once had a judgement against a teacher and that particular school district wouldn't allow teachers to have a criminal record of any kind, and they were automatically suspended without pay if they had outstanding judgements. It was pay up or lose the job.
Now at the same time, if these people are simply behind in everything, have gotten way over their heads I'd really attempt to make a deal with them to leave. Sometimes it's easier to simply offer them $500 to leave on a certain date leaving the home in broom swept condition. I find that a lot of people hang on and push when they don't have a leg to stand on because they really don't have the money to leave. One guy of mine couldn't afford to leave, because I didn't trust him with the money instead I litereally rented the UHaul for him, provided a couple of guys and moved him out. Threw him a few hundred and we were done.
The old saying is true "you can't get blood from a turnip." It sounds like these folks don't have anything so instead focus on moving out, negotiating the liens and reselling. You can spin your wheels going after them and still wind up with nothing. Instead, find a way to bump them along, you can threaten all kinds of stuff, but be willing to negotiate in good faith.
Honestly, by doing so you'll find a whole lot less damage inside the house when you do get it back.
Best of luck to you.