The CRS report should probably be considered a secondary source regarding the legal requirements for nominations and appointments. While it seems it is generally accurate it is not perfect. For instance reference 16 regarding the appointment of principal nominees to the USAFA shows 32 CFR 901.27, this would more accurately be attributed to 901.18:
The primary source for information regarding this issue related to the USNA, in my opinion, is 10 U.S.C. § 8454:
"Each Senator, Representative, and Delegate in Congress, including the Resident Commissioner from Puerto Rico, is entitled to nominate 10 persons for each vacancy that is available to him under this section. Nominees may be submitted without ranking
or with a principal candidate and 9 ranked or unranked alternates."
So while the wording is different, the fact that nominating a "principal candidate" is codified is significant. It should be noted that the Air Force and Army references are CFR and the Navy reference is USC. I don't know if this has ever been challenged but a good argument could be made that since congress wrote it into law...they intended that the USNA follow it.
Having said that I would not consider it a 100% probability even if the candidate is fully qualified, but I would wager it is very close.