fyi - The Ghosts clans are completely separate from the MW3/BO2 clans. They will be managed by the COD app which gets released on November 5th. So if you are just wanting to be a part of the Ghosts version of the clan, ask the clan leader for his application link. Again getting accepted into the Ghosts clan will not put you in the MW3/BO2 version but if that's all you want then it should work. If you want to get into the MW3/BO2 clan you'll need to log in through the MW3 side of Elite to get it to work.
When I invited my friends to my clan it didn't show up in his clan invites. Then when I try to invite him again it says that he is already in the clan it also say it for my other friends too . I only have one person in the clan and it didn't glitch out for him or me.