Merit listing is based on a single number that takes your CFAT, interview, schooling etc into place and gives you a ranking. Based on that ranking they make a list of everyone and when they make a cutoff date it is your position on that list that determines if you are given an offer or not. If for example you are ranked as a 69.4 and someone else is a 69.3 you will get an offer before them. Now that being said it is not a percentage so don't ask what the number actually means. The key and I know it is difficult is to relax because once you are merit listed you have no input into the system. You have done all you can do and that is it.
If you were to be offered a position to attend the NOAB it is based on that ranking so if there are 20 positions they will take the 20 top ranked candidates and make them offers to attend. If you were to attend and pass all the assessments and seem like you will have command presence etc then they will make you an offer at the end of the NOAB week. You may be the top ranked candidate going into NOAB and not get an offer.
Now as for some CFRC's being better than others. I don't think so. They are all busy and all have a lot of work to do. I would just relax and hope for an offer. Some may dedicate more time to you but they all get the information on the same day and they all make offers in the same sequence.
I have been there in the nervous anticipation of if I will get an offer or not. I know that it is difficult. Take up yoga, go for a run, hit the weights etc. Learn to relax or you will not survive NOAB without an ulcer and you will not survive your career without hypertension, a stroke or a heart attack. There will be stress in the career path you have chosen. You NEED to be able to handle that stress and channel it or there will be issues later on.