Just curious, was there a reason that you started him early on solid foods? My kids DR said babies systems are not ready till about 5-6 months old for solid food, is why I ask.
My suggestion now is to make his food, the jarred stuff is nasty! My son at around 10 months old refused any baby food as well as he would not let anyone feed him. The stuff you are feeding him now are actually pretty healthy, so I would not worry there. Cherrios have lots of vitamins. You can also try spaghetti O's (without meatballs), slightly mashed bananas, over cooked pasta, toast w/ jelly, etc.
Don't forget, he might not like something now, but he might like it eventually. My kids DR said it could take numerous times for someone to like certain foods. It took me over 20 years to finally like pancakes.