Sorry, it sounds like 20 questions but we need a bit more to be able to give a reasonable answer.
It matters what type of insulin regime are you using:
some mixed insulins have very distinct peaks.
If on the otherhand you are on MDI (a longterm + a rapid insulin for meals)- it is important to look at when the lows are happening .Hypos that are within 2-3 hours of your rapid insulin are more likely to be due to mealtime insulin mismatched with the food eaten, hypos outside the period are more likely due to the basal insulin or outside factors such as exercise.