There's two problems: One is that it's going to be hard enough with liberals getting all dewy eyed at the prospect of their dusky hued pets being sent home without forced labor.
Two: A surprisingly large amount of them are women that have children, what are we going to do with them?
If I were King of America, your plan is pretty close to what I'd implement, but for political expediency, I'd just let them deport themselves when they can't find a job.
As for issue #1 - yeah that is the Dems. Can’t help you with that one. Perhaps “hard labor” is the wrong term. My thought was a camp where people were required to work in order to earn their way out and back to their own country.
As for #2 - there are substantial number of support activities required to support a labor camp. The general rule of thumb is that there is a requirement for five times the number of actual productive workers to fill support roles. Barraks have to be cleaned and maintained, clothes and laundry has to be washed, food can be grown to feed the population, meals have to be cooked, daycare for the little ones, etc.
That is why the point system. Adjust the points so that the least liked jobs get more points but every job gets some points for their work effort.