New users being added to admin group once registered..
 

Usually, when a person first registers it adds them to the "Homies" group, but for the last 5 people, it has been adding them to Junior Admin group. Is there an option somewhere that might have been changed, that I might be able to change back?

Without modifications new members will be placed in the "Registered Users" usergroup. If you have installed a modification to change this default behaviour, then i suggest you look into that first.

What is the default "Registered Users" usergroup?

Registered Users is the name of the usergroup that all users get added to by default when you first install vbulletin. It is usergroup 2. You may change the name of that group, but unless you change the code, that will always be the first group that users are put into after they have registered (and verified if you have that enabled).