Hiding Extra Profiles when Manually Adding/Editing Registrant
Ah those are not profiles but custom data sets/fields.

Two tips:

1) Make sure that the custom data sets that you create are more specific than just on Participants -> configure it to also narrow down to a specific event.

2) Don't make the custom data fields within a custom data set required - but only make them required in the Profile - once you pull them in there. That way these fields are only required on pages that contain the profile.