Active vs Inactive Office 365 Groups

In order to do some clean-up for our Office 365 Groups we want to make sure that the groups that migt be considered in-active are trully that way.

According to this https://support.office.com/en-us/article/Office-365-Reports-in-the-new-Admin-Center-SharePoint-site-usage-4ecfb843-e5d5-464d-8bf6-7ed512a9b213?ui=en-US&rs=en-US&ad=US&fromAR=1:"Last activity date (UTC) refers to the date of the last time file activity was detected on the site."

We are not sure if a group would be active if:

1. There were conversations only (no files uploads at this period);

2. The team used only Planner;

3. Only the OneNote was updated at this period,

Which one of these users - groups interactions would trigger activity and which are considered "hidden' activities.