I show Jacques Mouse's quest line in my Achievement Guide here starting at 39:00 minutes into the video. Keep in mind that if you've already found one of the characters they won't reappear in your game until you find the collectibles that they want. I also have timestamps to the other characters down below.
GREETINGS, FELLOW HUMAN
El'iot T'yler: 0:36
SHREDDING THROUGH TRAFFIC
Nikki Stix: 8:19
EXTREEM PROTEIN!
Xtreem Mascots: 15:40
INFURIATING INTERN
Jerry Jones: 22:03
TOURIST TRAP
Sandy Miller: 30:56
MAINSTREAM VS. MAPLE
Jacques Mouse: 39:00
JUST SMILE AND WAVE
Risa Lopez: 46:46
CAST AWAY
Jose Rodriguez: 53:05
BREAKING NEWS!
Emma Ventour 1:00:40
PLUMBING THE DEPTHS - Mr Marino: 1:09:13