The methods I've used - depending on the effort and quantities involved - are either using Munki (as suggested by Mr Hoffman), or DeployStudio or ARD. It does make it easier using ARD seeing as you're using the same Apple ID. You don't necessarily need a script as all you need do is update all the apps on a single mac which would ideally be the 'admin' one (the one with ARD installed) and then use ARD to copy (and overwrite previous apps) updated apps to the same relevant locations on all the rest. You can schedule the 'update/copy' at a time convenient to you.
Another way would be to, again, update all the apps on a single machine and copy them to DeployStudio's Files folder. Assuming you have OS X Server and DeployStudio installed and working? Create a workflow that includes those apps and copies them to a convenient location; then add a script that first removes the older apps and moves the newer ones to the Applications folder.
Obviously test this first. Not just the workflow but also whether the apps launch successfully or not thereafter and are usable.
Once the workflow is set up and tested all you need do thereafter is, again, update one mac with the updated apps and copy them over to DeployStudio's Files folder and then run the workflow when you're ready. The workflow can also be configured to run on all or part of your mac estate at a time that suits you. Again you can use ARD to define a time of your choosing.
If it was me I would look at using/utilising Munki as this brings both the above two approaches together in one simple 'deployment solution'.
One further thing to consider is do you really need to update apps? If there's no compelling reason to do so then wait until the summer recess, re-create your master image with all the necessary updates and re-deploy to your mac estate. This method keeps things clean and fresh as well as removing crud and cruft built up over the period between rebuilds.
Hope this helps?