Overall I would plan on 2-3 hours including setting up the vehicle and cleaning everything up. For me, what took the longest was getting the O2 wrench to properly "grab" the nut on the horizontal sensor due to the flange getting in the way. Once I flattened it, it was a matter of heating up the exhaust hot enough (glowing red) so that the seized sensor will come loose. If I had to do this over again I could probably do it in an 1-1.5 hours or so because knowing where the connectors are for the sensors is half the battle as I had no idea where they might be starting this repair (thought they were hidden behind the engine although that wouldn't have been typical for BMW since everything is normally so easy).

No, I didn't do anything else while I was doing this repair since there's really nothing else that gets affected/removed.