While there is lots of useful advise in there, I wonder how do you measure a "successful" termination process? What differentiates a great "we have to let you go" meeting from a terrible one, output wise? What's the metric you want to optimise here? Future references?
They're still your friend in 5 years or more, long after that job.
I did a mass termination many years ago, and those guys are still in touch with me. I made sure to telegraph that things weren't going well for the company.
One guy had a pregnant wife at home, he still laughed it off. Wrote to me the other day.
If good news happens a month after they are gone and you want to hire them back are they willing to come back or do they continue to find a job elsewhere?
