The O2 sensors have nothing to do with the heater hose. You might know that but from the sentence structure it was implied.
Your mechanic should have been able to figure out the O2 problem. Even with a new part it's a pain in the ass and could be a catalytic convertor problem. I recommend you buy a ODBII to bluetooth reader and use your smart phone
Use your iPhone to Scan Vehicle Codes And Read Sensor Data
The hub is easy however you are going to need a press to get the bearing out.