Here's what I posted in the Toni G. thread - and it's just as valid here:

I totally disagree that this name should be treated as a stage name.

Just because the last name has been shortened to an initial I don't see this as a stage name.
Why is this any different than someone shortening/adapting their first names.

For example: Actor JB Blanc (as he is usually credited).

Real Name: Jean-Benoît Blanc.

We don't treat this as a stage name so I see no reason to do so with Toni G.