I got a new 6 inch silver aro a little over a month ago and he did the exact same thing. Wouldn't eat the Hikari Cichlid Gold pellets that my first aro loved nor did he touch crickets which was strange because thats what the lfs fed their aros. I randomly threw flakes in there and he started eating, lol. He was on a diet of flakes for next month with me randomly throwing in some pellets to see if he would take it, but he didn't. Just last week, since he is approaching 8 inches, I decided to starve him out until he accepted the pellets and guess what, it only took 1 day without food, lol. Now his main diet consists of Hikari Cichlid Gold and he seems more excited about feeding time. I think your Jar is just too small and needs some time to adjust so don't give up! Also I would avoid guppies, not so good for the Jar, especially while young and you don't want it to get hooked on them. Good Luck!
Btw, Woot for being a fellow SoCaler!
Btw, Woot for being a fellow SoCaler!