These type of abnormal behavior arise from general electrical failure from relay tripping or misbehaving. Check all the fuses and relay and se if some needed a change their.
oil leak can be from engine, gear oil, power steering leak, brake oil leak.
Leak from engine is from engine oil leak and common places to doubt is crankcase, oil sump, engine head etc.
Better check engine oil level regularly until leak is fixed.
Melted electrode A symptom of severe preignition. The spark plug has been running too hot for a long time. This can be very damaging and may burn a hole through the top of a piston!
Overheating If the spark plug insulator is blistered, white and free from deposits, something is making the plug run too hot. If the heat range is not too hot for the application, check for cooling problems, incorrect ignition timing or a lean fuel mixture.