Concerning your mistake:
If there is a discrepancy between what you declared in your EE profile and your employment documents, then yes you should definitely correct it. If the mistake is in the reference letter, you need to provide them with a new one via CSE webform. Don't take too long though! Eligibility usually starts roughly around 80-120 days post-AOR. See if you can upload the new one before application reaches eligibility stage!
Concerning your NOCs:
Unfortunately, these mistakes of wrong NOC selection is quite common. But I really hope it doesn't cause any trouble. There have been numerous cases in the past where experiences were invalidated and CRS/FSW points recalculated. A fairness letter is then issued to inform the applicant of situation if he/she falls below points thresholds.
Thankfully, you have just above 1 year even if they invalidate jobs [3], [4], and [5], lucky you! And I believe the NOC is correct, with correct duties.
I see your CRS and FSW will still remain above thresholds! I think you should be fine!