I haven't read through this case extensively. All I can say is this.
1 - Maximum points can be claimed for up to 3 years. You get no additional points in CRS for anything more than 3 years. Up to 6 years can be claimed for the FSW 67 points needed to qualify for express entry. However assuming your crossed that threshold, you can only get points max for 3 years.
2 - For CRS, mix and match of NOC works. For FSW eligibility, you have to choose experience gained under a single NOC - that scale maxes out at 15 points for 6+ years of experience. Under EE, this is termed Primary NOC. So your primary NOC experience determines your program eligibility (in part) while for CRS purposes, you can have other NOCs as well provided they are 0/A/B and acquired within last 10 years.
3 - The NOC should match the work experience. It need not be point by point but it should overall match the spirit of the profession.
4 - If you made an error in NOC and it does not match and if you claimed points for it, and once the VO re-calculates it and it falls below the threshold of the draw points when you are invited, you will be rejected.
5 - You can try a CSE. No guarantee it will be considered.
This is what I know - Based on the best of my knowledge.