Would it make it safer if I plugged each light into different outlets?
If by safer, you mean fire-hazard, life safety, then: assuming the house is wired according to the Canada Electric Code (or fairly equivalently for these purposes, the US National Electric Code), and assuming the lights are not sketchy products (i.e., UL listed, in good condition), then you don't really need to worry about safety in this regard. You might overload a circuit, but you won't actually cause a safety problem.
However, if by safer you mean the broader sense of not wanting to cause any issues at the shoot location, then you are right to be concerned. Alan Marcus's answer is spot on — it's possible you could cause incidental property damage to sensitive electronics.
You could try to plug into different outlets, but that won't matter if the other outlets are also on the same circuit breaker.
In order to determine what outlets are on which circuit breakers, you need a circuit breaker finder, which consists of 2 devices: a plug-in sender unit, and a non-contact sensor unit. You plug the sender unit into a wall outlet, and then at the circuit panel you wave the sensor over the circuit breakers, stopping over the breaker where the sensor squeals loudest. You have just identified what circuit the outlet is on. Go back to the outlet, remove the sender unit, and plug it in to a different outlet. Go back to the breaker panel, wash, rinse, repeat.
I used to set up 4–16 "PAR can" stage lights for a bar band (in addition to sound gear and amps). We used to blow breakers all the time at some bars (their outlet situation was notoriously bad) before I committed to mapping out which outlets went to which circuit breakers using a circuit breaker finder, so I could spread the load. We quickly got a reputation for being the band that knew what they were doing and were responsible and conscientious contractors at the venues. We were professional, and always got callbacks.
Based on my experience, at 3/4 to full power, your light kits will definitely blow a 15A breaker, and probably a 20A at full power. Plan ahead. Also, plan for heavy duty extension cords (25 ft each), and gaffer tape to secure the cords to the floor, so an accidental trip won't knock over a light, damage property, or possibly even start a fire.