Originally Posted by pravado
so your advice would be either do these on my first playthrough, or should i just wait until ng+ to even bother?
also a list of unlockable characters and how to get them would be sweet. i dont wanna miss anything on my first runthrough besides jet ranks if i can do those in ng+
It depends if you want to have to do a full second playthrough. Technically it's possible to earn every achievement with 1 and a half playthroughs.
When you first play Grind Square and Bantam Street, only Combo & Cube are available. Neither of them have max graffiti rating so it can be hard (but not impossible) to Jet those levels. On subsequent playthroughs you'll have access to every unlocked character.