@Everett Lee , Welcome to Microsoft Q&A, you could try to use Type.GetConstructor Method to get the correspond Constructor and use invoke method to create the instance.
Here is a code example you could refer to.
Assembly assembly = Assembly.LoadFrom("ClassLibrary1.dll");
Type type = assembly.GetType("ClassLibrary1.Class1");
object [] paramValues = new object[] { "Test1",'1'};
Type[] paramTypes = new Type[] { typeof(string), typeof(char) };
object instance=type.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic,null, paramTypes, null).Invoke(paramValues);
Result:
Best Regards,
Jack
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