From my researching so far this is my reply to your specific concerns.
1. You won't die, some people are nervous around chemistry, just like people that are afraid to fly. You just have to use common sense. From what I read, it can be possible to overheat the solution and cause it to work much faster than intended. When it works much faster, and you don't take it out soon enough it can cause "blooming" (whitish discolored areas)
2. See "blooming" above. If you leave it in too long, make it stronger than recommended, or use 700 UV lamps, put the lamps way to close thereby overheating the solution (this also depends on the surrounding temp of your enviornment).
3. It does come back, and I am
sure that is indeed angry and wanting some vengeance indeed. Using a clearcoat stops this in 2 ways:
Discoloration can't come back because it can't get a ride from oxygen. Discoloration doesen't have a car and is always mooching rides off oxygen and UV to go to the comic book store and over to your house to get revenge. Clearcoating puts up one huge detour / road closed sign and Oxygen gets lost (no GPS). The UV inhibitor keeps UV from seeing "where discoloration be at", thereby preventing UV and discoloration from going in and "Jackin' yo Bromine bro'".
No vengeance and no jackin' means discoloration is stuck at home in mom's basement being bored.

Ive heard horror stories about this retrobrighting. Some telling me ill die if I try, some telling me it'll go blotchy and now this telling me it'll come back with a vengeance. With all this in mind I've bought a swcond hand case in good condition on ebay and a brand new keyboard. That should do the trick. 
Will post any pictures I get of the old monstrosity vs the new gleaming case. 