Thank youuu!! Crisp's also my fav! I've created him a couple of times in Sims 2... once with CC, and once without CC. (Because I wanted to test the Legacy release without mods / CC)
Honestly, I find it easier to make Sims using the Body Shop rather than the in-game CAS. Not sure why that is! But Body Shop seems more customizable, my Sims always come out better when I use it first! ^^;
As for Darius... I think the age MIGHT only apply to his Handheld self, and you can argue if his console counterpart is supposed to be the same age. But considering Jayde's the exact same age (21) and all the confirmed ages are super young -- it's semi safe to assume that Darius is likely 21. Heck, you'd assume Mazuiko is somewhat older, given she's a former stripper + restaurant owner, but she's literally only 18 years old. That means she was either a stripper for only a few months, or there's some disturbing implications there.
I think they kept most of the Urbz very young (with the exception of obvious older characters like Louie Bricks) because the game emphasized that it was the "cool" sims targeted towards the young adults, and it focused all on young adults + trends rather than domestic family life. Therefore, they likely didn't want to make too many of the characters older than 25 'cos they didn't wanna turn away the target audience (teens + young adults) with MUSTY OLD CHARACTERS.