considering network bandwidth to handle large amounts of file and size -  optimized/dedup assets - disable workflow- if disabling is not an option customized to keep only required steps - if disabled, rerun using the profile for specific folders/files- increase CQBufferedImageCache consumes heap dur...

consider using a permission manager and plan to have user groups with users and specific access control for each user.https://experienceleague.adobe.com/en/docs/experience-platform/access-control/abac/permissions-manager/permissions 

there is no limit as such, but try to control user delete action with permission and limit user access control 

consider below - Project> document Tab>action/permission > add/remove user permission - on the box instance control permission for the same user and block accessing the box 

consider below using fusion - Create a new Scenario> Trigger Module -  Watch Record Updates > Configure Trigger module for task, field to watch/trigger > add search module to find project owner and project owner id /email address > Add email module > Configure email module

Create a new scenario > Setup/ configure trigger module  > Add search module to search for a program where the update is required > Add update module to post an update in the identified program> Compose/add a message for identified program update

think of below - Name/title each scenario and use the report to track the number of scenarios and filter based on name/title- Create a custom field and using fusion create a trigger to update this field each time scenarios runs @Lawson02 

you should look into data distiller module , required license from Adobe to bring in model / train model  Connect to Data Distiller from a Jupyter Notebook | Adobe Experience Platform

think about below option - Created a data source [storing email id in your region ] with a GET call to an external API to pull the data.- Used update activity to update profile data with the data received from the GET call.- Journey created to use the updated profile data to personalize. 

Please refer below documentation Configure permissions | Adobe Experience Platform