Thanks for the input! My update: I started out with the cupcakes on racks and used a silicone brush to apply the soaking syrup. I got frustrated fast and wanted to use a syringe, but didn’t have one.
Then I got the bright idea of calling the local pharmacy. They gave me a small syringe that is used for squirting medicine into a baby’s mouth. It holds 1 t, just enough to moisten a cupcake. I injected each cupcake in 1-3 site(s). It went fast and made almost no mess. I can’t tell yet if the cupcakes are evenly moist; at the initial tasting, the syrup hadn’t distributed evenly, but I let them sit and I’m going to taste them again tomorrow.