What you can do is use the Windows Installer API to dump all the DLLs contained in a given MSI package.

In C#, there are various libraries or sample code available to do this.

Here, I will use the open source Wix toolset project's DLLs. So, you just need to download the binaries (not the wix installer), create a project and add references to Microsoft.Deployment.WindowsInstaller.dll and Microsoft.Deployment.WindowsInstaller.Package.dll in this binaries directory

Here is a sample program that writes out all DLL files part of the package.

class Program
{
    static void Main(string[] args)
    {
        string path = @"... myfile.msi";
        using (InstallPackage package = new InstallPackage(path, DatabaseOpenMode.ReadOnly))
        {
            foreach (var kvp in package.Files.Where(f => Path.GetExtension(f.Value.TargetName) == ".dll"))
            {
                Console.WriteLine(kvp.Value.TargetName);
            }
        }
    }
}

}