my only concern is how secure these systems are,
Extremely! Roller coasters are no problem at all.

like whats the odds of them coming off or the hairline lifting up ,
Odds of coming off if attached right are 0. Hair line may lift slightly as the days go on, but u can use glues to touch up, no big disaster there.

also can you swim in them ,work out in them, sleep in them, etc,
Yes, yes and yes, all no problem at all. Gotta use common sense here, if your on day 15 and u feel its not 100% secure but secure enough for regular activities, you might want to think twice about jumping in the ocean. I recommend a very strong tape bond if u want to go swimming. Better safe than sorry in this situation.

whats the best glues and tapes to insure a good secure fit,

This is really a personal choice and how long u want to attach for, No use in using a super strong tape or glue,if u want to remove every 2 days. I remove once in 20 days, I use Tight Grip glue for front touch ups and Blue liner tape for the rest, although super tape i heard is not bad to try as well. You need to do some experimentation to see what works best for your needs and lifestyle.

Sam