I have a layover in YVR (Vancouver international airport) from roughly 8:10 pm to 7:30 am. I don't want to spend money on a hotel or a "sleep-pod"/equivalent. I will most likely bring a sleeping bag and pillow. Other things to note:

I am a very light sleeper and will be wearing heavy-duty ear plugs.

It is *crucial* I get at least 8 hours of sleep and will therefore take soporific(s).

I obviously can't miss my flight.

What is the best way to sleep in an airport, while spending little to no money? 

Ideas I have thought of:

1. Set a high-volume alarm on my phone, 30 minutes or so before boarding.
2. Ask a flight attendant or other airport employee to wake me - possibly in combination with (1)
3. Ask another "layover-ee" to wake me
4. Tape a sign above me with an arrow pointing downward that says "Please wake at 7:00 am! Will pay $5!"

Ideas, please?

EDIT:

I am *not* worried about theft of my possessions. I will simply put all my, very small, valuables (phone, wallet, passport) at the bottom of my sleeping bag. This is assuming that I will wake up, should some idiot attempt to pull me out of my sleeping bag to steal my valuables..I also do not have a carry-on. 

The main thing I am concerned with is missing my flight.