Multiple lights/ceiling fans on 14/2??
Darren, I can see where you are confused, so let me try to help you understand better.
You are correct that 12 wire goes on a 20 amp breaker and 14 wire goes on a 15 amp breaker.
You misunderstand the aproach to sizing a circuit.
The first step is to calculate the load on the circuit.
Lets say we have 32 ea 60 watt bulbs. 60/120 = 0.5 and 32 x 0.5 = 16 amps.
Once we know the load we look next at wire size. A 16 amp load is above 15 so we would use a 12 wire. Last we size the breaker. 12 wire is good to 20 amps so that is easy.
We now can either use a 20 amp breaker and number 12 wire, or divide the circuit into two so as to not overload a 15 amp breaker.
I do not know the code in Canada, but I do know the NEC. So, before we argue the clause that in residential work, general purpose lighting outlets have no load, (meaning no load calculations need to be done on these circuits) lets move into a real installation where if we overload the circuit the breaker will neusance trip.
Sorry for the run on sentence, and I hope you understand this better now.