To help anybody out that may have these problems in the future:
Passenger airbag showed resistor too large. I had no idea how easy it was to pop the passenger airbag cover off. Found that the connector had been disconnected. Turns out the previous owner was a bag of crap and had disconnected it. Great guy apparently. Reconnected the connector, reset the light, and I'm now down to four codes!
Pulled out the driver's airbag and found that the connectors that plug in to the airbag were damaged. I fenagled one to work as a test and reset the light. Now only three errors! I will order the new harness and expect this one to be resolved.
So in my case, resistor too large indicated an airbag not plugged in. Resistor too small indicated a damaged connector at the steering wheel. The airbag itself has a spring in the connector that shorts to the pin, and I think when the cable is damaged in allows the spring to contact the pin, creating a very low resistance circuit.
Next step is to look at the seat belt tensioner. Resistor too large = it's disconnected? We shall see.
I'm still at a loss for the battery unplug fault. I'll look more in to this one in the next few days and post my findings.