does your hydrometer tell you that it is done fermenting?
if it's below 1.000, then its probably done. if its done fermenting, you won't get bottle bombs unless you add way too much corn sugar. i don't bottle anymore, but the normal amount was 3/4 cup, but i used to go by weight because it was more reliable. i also used more than that because i like cider a little more heavily carbed. if you are using cheap bottles though, this can be a problem. one cup corn sugar should be just fine. after cold crashing though, it may take as long as two months for that to carb up. i have a cyser bottled in grolsch bottles that is just starting to carb up after a month.
cold crashing doesn't kill yeast or anything like that, as it seems your post implies. it just drops the yeast out. it is still in there though and if things aren't done fermenting, they will eventually explode as yeast levels build back up. trust your hydrometer, it is your friend. do not trust your airlock, it is your enemy.
