Hi and welcome to Arturia forums.
You can use Arturias plugins and presets in Mainstage. But it's not like the presets are in a Mainstage format, before you create a patch yourself. You should be able to use Arturias preset browsers to find presets for your Mainstage Patch.
I assume it's the same for any third party plugins used in Mainstage.
So this question is perhaps more about using Mainstage. I can suggest to ask in a Apple/Logic - Mainstage forum, and to search tutorials.
Also keep this in mind, if it's still like this:
https://www.arturia.com/faq/utilization/my-preset-sound-changes-in-mainstageI use Windows. An apple and Logic - Mainstage user i assume can tell more.