On free an personal plan, you are on a server where you share capacity with other apps. This mean that another app can affect your app speed and workflows because you share server capacity. In pro and prod plan, you have reserved unit capacity, so your app is not affected by other apps.
Scheduled workflow. Bubble talk more here about scheduling Recuring WF. They are backend Workflow that you set to be recurring. Depending of the plan, you will have different options for the recurring time. (each day or each month). [New Feature] Recurring workflows
White labeling mean that you will not see the Built on Bubble banner at the bottom.
On free and personnal plan, you have 1 dev version. But in pro or prod you can have more. This mean that you can work on one version and someone else can one on another version and you can push live each of them independently. So if the first dev update is ready, you don’t need to wait for the second user to complete before pushing live. Usefull when for example, you want to make an update that will take time to develop while another version is used for quick fix of issues submitted by your users. [New Feature] Multiple versions
for logs, I highly suggest you to check in your apps to see what is logged by Bubble. Check your logs tags and enter a time period to see what was logged. Also, click on advanced to see more things.
To know more about sub apps: Sub Apps - Bubble Docs
File storage are just for file. So any file you upload to Bubble goes to an AWS S3 storage. This will use your storage limit. You can always store your files somewhere else (your own S3 storage for example).