I really like this idea because you can kinda switch off from doing quest and trying to get stronger, so pretty much you can do semi quests of self improvement and feel better about yourself. The bonuses shouldn't be that strong, because when they add up it gets a little too crazy. one more thing is that there is way too many achievements. i counted over 160. the only way that i could see that working is, e.g.
the achievements for the secret maps. when you achieve it you get a secret dweller level 1 achievement, and the bonus for this achievement is +2 health. For however much more you need to get the next achievement you will get the secret dweller level 2 achievement which instead of +2 health as a bonus you will get +3 health. This would categorize things better and would make things not everywhere around the place. One small thing is that some of those achievements are a little too simple. Maybe one day i will be doing something ordinary and regular and suddenly for doing something simple i'll get an achievement. This will lower the challenge level of achievements, therefore making them not any fun because it will become more repetitive than adventure. But we do want to put some easy ones also but something like kill a charred snake, bat, and scorpion within 2 minutes. simply it achievements will be a new form of quests.