QUESTION 1: A 2way speak is just a speaker that has two drivers built into the cabinet. Now most speakers tend to be three way, the reason cause you want to have a high, mid and a low frequency to experience the full range of sounds being replayed on your music or movies. Now that doesn't mean a 2way can't do that, that's why there are full range speaker drivers which can act like a mid and a woofer at the same time, it just has a frequency range that goes really low and comes up decently high. I would say having a 3 way speaker is better because each driver can focus on doing one thing really well and they can be protected better with crossovers which send the right frequencies to the right speaker.
QUESTION 2: A passive speaker is a driver that is not powered by the amplifier, it is passively moving using the compressed air the other driver is producing. that is why most passive drivers are bass drivers, they are easier to reproduce requiring very little tuning. example is you could have a speaker cabinet with 4 drivers, one tweeter, mid driver, woofer and a passive acting as another woofer. This can make that speaker unit create more bass with less amplification. A good way to notice a passive driver is one of the woofer's wont have a dust cap in the center of the driver protecting the voice coil cause there is none, its usually a flat looking speaker.