Yes, it is possible to make fire-breaks where the fire can be handled.

They have to be very large (and therefore expensive. Both in terms of land and in terms of maintenance) to protect your house against a mega fire though.

Of course, they could be created in preventative fashion to limit the fires so that the size of the forest fires is limited.

While it would have to be "large" for a "mega fire," there are a lot of small and inexpensive things you can do to help protect your home. Things like removing any shurbs around your house are very useful. Won't necessarily save your house, but it's a good start.

Yes it is, and it's actually pretty easy. There are many ways to reduce the chance of a fire hitting your actual living structure and out west there actually are landscaping firms that specialize in doing that. Unfortunately many older homes/properties aren't set up for this so that's when it can get expensive.

Source: I'm a wildland fire fighter. Have seen awesome and terrible uses of fireproofing property.