Those were nicknames.
Hey! I know a good first name when I see it. I'm going with Nuke-Nuke, Boutros-Bourtos, Sirhan-Sirhan, BeBe, CeCe, DeeDee, GiGi, Bling-Bling, yada yada....
;-)
I agree with you that those names are nicknames. All my nieces and nephews call me Aunt Muggs. Muggs, of course, isn't the name on my birth certificate, thankfully.