Not really. The bee that stings you will flap her wings very vigorously, and it will rip its stinger off in less than a second trying to get away from you. Unless you're deliberately trying to get stung and save her, you won't have a chance.
Depends on the colony. The bees that have stung me have always taken 5 or 10 seconds to start trying to dismantle themselves in earnest, which (depending on location) is usually enough time to rescue them. (I'm not sure whether they survive my rescue, but at the very least they can fly away, and their stingers don't remain in my skin.)
The barbs don't catch on an exoskeleton like they do for thick and elastic mammalian skin.
An elegant way to deliver more venom to larger targets.