Feed is the part of Vibebo where published content and activity can be surfaced for discovery and engagement. It gives users a place to interact with content that has been intentionally made available there.
VibeboX is part of the wider Vibebo profile experience and brings together public facing features available to an account. What another person can see depends on the features you have enabled and your visibility settings.
No. Private messages and private account information are not automatically turned into public content. What is published or shared depends on the action you take and the visibility controls attached to that feature.