I'm not sure about this bit - "it is often recommended to do a side-deal."
There are pros and cons. Look at the cons first:
1. It is not a clean break so there is always the possibility of something, anything, going horribly wrong.
2. Is it legally effective? Possibly , but see above.
You can never stop people coming back whining later. Which is why the clean break is so much more preferable.
3. You still have the liability but without the asset.
4. You still have a mortgage.
5. You do a runner and the house is stuck in limbo in joint names,
I'm not sure that there is any legal answer to that.
But, because people are stuck in these awful situations, it is tempting to look at the situation positively.
Pros
1. There is an interim solution.
2. It gives breathing space
3. Selling the property ( realistically what they should do) is not a palatable option.
Overall, I would not like to try and make it "stick" because of all of the variables. But, if people can agree, and can be relied on to be honorable...........maybe its worth a shot.
mf