Toyota Repair: 1997 Toyota Avalon, toyota avalon, o2 sensors

Question
1997 Toyota Avalon 6 cyl 3.0 L DL 191,000 mi exel cond.

Check engine light came on. First time. I went to Advance Auto Parts so they could pull the codes. The results are as follows.

Global OBD II
DTC (Codes)
PO135
O2 Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 1)

DTC Pending (Codes)
O2 Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 1)

Please confirm if there are two or three O2 sensors ? My research on the Auto Zone website says three. While at Advance the look up by the clerk and my later online look up says two ?

Which one is Bank 1 Sensor 1 ? I clearly see the one in the manifold near the radiator. Is this the one that says to be replaced ?

Should I use some anti seize on the new sensor ?

Is using the Universal repl type with the pigtails ok at $65 (I realize all elec conn, crimps can be problematic at some point). No problem for me crimping the terminals however, I guess to the connector cut off from the old sensor ? Or use the OEM repl with connector already attached at $120. Any difference ?

I'd be glad to save the money since my job went to China last year. I'm back to doing all of my own work now.

Thanks a lot.

Steve
Greensboro, NC  

Answer
There are actually three sensors, two in each exhaust manifold and one behind the catalityc converter, the one you are referring to is the one near the firewall in the exhaust manifold(B1S1) you can use the universal type, I don't know anything about them so follow the instructions that come with it.