Hi @JFK. There are various ways you can use Foundation.
The simplest way is serving it via a CDN, like you’ve observed in the templates.
Alternatively, you can download a copy and host on server as well.
Either way, any changes you make generally are made in your own CSS/JS files on top of Foundation. You don’t edit the Foundation files themselves in this setup.
This method is generally fine if you don’t work in a production workflow with pre-processing and the use of SASS, etc.
If you want to utilise SASS you’d integrate that into your production pre-processing and host the compiled files on the Treepl servers.
More on Foundation usage options are here:
https://foundation.zurb.com/sites/docs/installation.html
From what I understand, the assets bundle give you these pre-processing files so you’d have access to the SASS and whatever other processes they have set up.
If you purchase these files, process them correctly and upload it, it wouldn’t make any difference to a fresh template site - but since you’ve made changes to the template already you’d probably have re-do CSS changes in the SASS files. Most other changes would probably be fine.
But no, you still should be able to change any effects as these would likely just be CSS based or controlled with Foundation data attributes.