I agree with the concepts, but there's a risk to this. These people collect welfare for a reason. They're not achievers. They're not known for their accomplishments. Government is already plagued by substandard poor performers. Many of these people would just serve as unnecessary burdens, and their "required" contributions would be worthless. It could end up costing us more in the end.
As an alternative, establish additional qualifications rather than just the needs-based initiatives. Require that they obtain training, financial/economic as well as job/skills. Just thinking...