Percy D. Mitchell III joined the Law Offices of Jeffery M. Leving Ltd. as an attorney. He has expertise in family law, having litigated tough divorce, child custody, child support enforcement, parentage, order of protection and paternity cases, as well as cases initiated by the Illinois Department of Children and Family Services.• Mayer Brown LLP promoted John-David Treumann, Michael Taylor Neidigh and Tyler D. Alfermann to counsel, effective Jan. 1.Treumann has experience in a wide variety of asset-backed and …