The oil level warning can sometimes take 30 miles or so to reset, for no obvious reason. The sensor talks directly to the cluster and has nothing to do with the brake pad warning. It uses a bespoke serial interface to send oil level, condition, and temperature. Make sure there are no related faults stored in the cluster as otherwise it will just ignore the sensor.
The pad warning is usually caused by a bad connection at the caliper. Clean up the contacts, sometimes it helps to use a pick to bend the sockets of the car-side connector inward slightly so they make better contact with the pins on the pad-side, give them a spray with contact cleaner or WD40.
Its possible to bypass the warning completely at the plug in the front of the left wheel well - just ground the relevant wire. But, its usually not that hard to just fix it
