The outline only picks up the text from the "headder" text box in PowerPoint, there is no way to change that. You can edit the display name in the slide manager tool, and that will update the text displayed in the outline.
If you hide a slide in PowerPoint, then is will not show in the outline. The presentation may skip it, so you should test and adjust the Go To property in the Slide Manager or put in Hyperlinks to point to that slide. Hidden slides will display in the Quiz pane, so keep that in mind if you have a quiz.