I believe nothing has changed about Street Grimoire.
But, just like some Metamagics in the Core Book, the few Metamagics in Forbidden Arcana have not been assigned to any specific school.
However, I believe Tarot-Summoning and Hapsum-Do offer quite a strong hook for both role play and specialization.
And roleplay is kind of the key here, as those "schools" of magic were even less rigid than magical traditions; Unless it specifically said so, you didn't necessarily initiate in that order or follow the laid out course strictly.
After all, most characters in SR5 don't really have a background of attending a magic course in a prestigious university.