Doubt you bought a lemon. Once fixed your car will most likely be OK. While you have several codes, many of them may only require a flash. I get the feeling you do not have an extended warranty on your car, since most if not all 2005's are past their 3yr/36k mile warranty. Not sure, but maybe some of these codes/fixes fall under the Federal Emmissions warranty which is 8 years/ 80k miles.
There are these TSB's that refer to some of your codes. Not all TSB's apply to your 2005 car, but they still may fix your car.
p1521- Incorrect engine oil type.
http://www.wkjeeps.com/misc/LX/TSB/TSB_1800808a.pdf
http://www.wkjeeps.com/misc/LX/TSB/TSB_1801806.pdf
P0406 - EGR Position Sensor Circuit High
http://www.wkjeeps.com/misc/LX/TSB/TSB_1802707.pdf
P0430 - CATALYST EFFICIENCY (BANK 2)
http://www.wkjeeps.com/misc/LX/TSB/TSB_1801107.pdf
p2112 Electronic throttle control unable to open.
http://www.wkjeeps.com/misc/LX/TSB/TSB_1801806.pdf