I've added Naked juice to a beer before. Turned out okay and didn't get the vomit flavor I've read about. I added two pints to a heavy porter. Only had a hint of flavor. I'd recommend an extra pint or two if you go that route.
Dump em in! No bag! Beer is pretty forgiving. Just do it. That's how I go. My experience with bags and carboys has always been a PITA. I don't even bother with bags or carboys anymore; straight from bucket to keg anymore.
I did in the beginning, but not anymore. Only if I somehow kick up the sediment in the keg. My mom, however, won't drink my beer anymore because it hits her so bad. I had to start filtering because of her.