Here is one black bear I killed with my bow @ 18 yards stalked on the ground. He weighted 750 lbs. with a skull measurement of 22 1/4", I was by myself without a guide backing me up. Some people live in fear and others don't.
To respond to your 3rd question, I would choose slugs for that type of situation. Unlike you, I base my opinions on experience, not hypothetic reasoning without any bear hunting experience.
I would have no issues bow hunting with a guide backing me up with a rifle, or hunting with my 300 Win Mag.
As hard as I try I sometimes have a hard time taking the high moral ground, so here is my response:
Congrats on being a bada$$!!! But your bear is still half the size as the ones mentioned! You also have no experience with BIG bears so try looking in the mirror once in a while...and not to just totally admire yourself!
I once had to shoot a large angry charging pit bull with a .40 S&W, does that count?
As far as living in fear; I'm career Military (Sniper, Infantry- Airborne/Air Assault/and leg) and have been on more than one combat deployment, one of which the company I was with had 147 enemy engagements and encountered 90 IEDs. I received a medal of valor that deployment.
So all I can say to you is pump your brakes a little there tough guy, and go on your occasion life threatening hunt...
Now I'm gonna be a hypocrite and take my wife and kids to church...hope you enjoy the rest of your day while I get mad at myself for stooping down to your level.