Is there a name for the tabloid media practice of part-initializing, part-abbreviating people's names?
E.g. Jennifer Lopez -> J-Lo, Robert Pattinson -> R-Patz and so on.
I would say it's a diminutive, or a nickname (although nickname implies somewhat more familiarity to my ears, it is used in the news as such: “Jennifer Lopez, known by her nickname J-Lo”).
I think you could probably just call these nicknames — they are highly stylized nicknames, but nicknames nonetheless.