The car will run fine with the CEL for the Rear cat. That Rear sensor is there for that reason, cat deficiency, just to tell the driver they are polluting a little more than planned and they need to fix it. This usually happens years down the road.

The cruise control blinking could be a different issue.
Try to clear it out. Unplug the battery for a few seconds, maybe a minute. Then turn it on. The CEL will definately come back on after driving it a bit.

You can go to Autozone or Discount Auto and the will pull the code for you and let you know. They can also clear it.

By the way I've been running with the CEL on for about a year now. I never ordered the damn CEL fix. I do have a code reader so I check it every week or so to make sure there's no other codes in there. I really need to order this thing.