Not exactly.
A Presidential nomination is not competitive, it is given automatically if the candidate's parent(s) meet the criteria.
There are an unlimited amount of Presidential nominations, but only 100 appointments can be selected from those unlimited nominations.
Correct, but every candidate should also understand (as I know you do mom3boys) that they should not rely on the Presidential nom only, they should apply for each and every nomination category that they are eligible for, even after you are assured of your Presidential nom. This gives the academy a lot more "leeway" in admitting/appointing the best class from all possible sources.