One light and a reflector should work.
One thing I would be worried about is the amount of light you will need. A regular incandescent bulb doesn't really put out all that much light. I'm just guessing, but with something like a 250 watt bulb...you would have a hard time getting enough light to light up one whole person.
You might consider something like halogen work lights...they are quite bright...but they get hot, very hot in fact.
Are you planning on using anything to diffuse the light? Light from small source like a lamp or work light will be very hard or harsh. It can be useful for dramatic lighting...but for portraits, it usually doesn't look too good.
You can make some sort of diffusion device but be careful if you use 'hot' lights.
Check this site for DIY stuff
You are going to want to test out your set up, before hand. Especially if you are not sure if it's going to work. You may be better off just using a flash on your camera. A good hot-shoe flash can easily provide enough light for portraits and small groups...the only problem is that the light is still close to the camera. If you can bounce the light off of a wall or ceiling...it will really help. You can even buy or make some sort of diffusion for a flash unit, that will soften the light.