i agree with most of what has been posted. the best protection is building defensible open areas into the landscape around your buildings, removing ladder fuel and things like woodpiles and fuel storage tanks, and using fire retardant building materials or protectants.
that said, i disagree with the underground water storage unless you have good battery operated pumps or generators to get the water out. often, a wildfire will take out electrical to your property before it gets there. that means wells don't work and you can't pump water. better to put the tank on stilts so you can gravity feed if you need it that badly.
another option is to get a pto pump for the tractor and put it to work pumping water either out of an underground tank or from a creek/stream/pond etc. you can run a lot of hose and move a lot of water with a tractor pto and a good pto or wagon mounted reel.
on what a bx can pull, it can pull a lot more than what it's rated for, but the safety factor goes down. i pulled a tandem axle trailer full of wet sawdust around the property yesterday. without the FEL in place, the front wheels were barely skimming the ground and turning was a slow and tricky process. i would say trailer weight with load was in the neighborhood of 3-4 tons and there was definitely too much tongue weight. i would not have felt good about doing it on anything but flat terrain and not with any kind of additional stresses like a wildfire coming at me. having the FEL in place and something in the bucket would have helped. that said, i ran it at or near idle in low gear and the machine did what i asked it to do and there was no damage.
amp