It's not a confusing question. So, along with being a really cool dude with great hair, I am also currently at the schoolhouse and intimately involved with the CRO/PJ crosstraining selections (called "assessments and selections"). I say this for 2 reasons- 1, to make sure you know how cool I am. And 2, so you have a frame of reference for the information I am gonna lay out.
If A1C John wants to commission, he applies for the CRO process, involving a Phase I (paper packet) and Phase II (Assessment and Selection). If he makes it out of Phase I, he attends Phase II, or CROAS. CROAS is a 7 day mini-indoc, meant to select only the most physically fit combat leaders (or those that have the potential to be combat leaders). Along with physical evaluations, there are psychological evaluations, boards, and other events meant to holistically evaluate CRO candidates, including PJ's that want to be CROs.
If selected out of CROAS, A1C John completes any necessary school for his degree, and attends his commissioning source (OTS).
This is a nuance that some people don't understand fully- but Combat Rescue Officer and Pararescue are different career fields. While a lot of the things we do are the same (shoot, move, communicate, employ) they are two distinct career fields and require different Initial Qualification Training. Just as a PJ isn't a CRO (and vice verse), CROs attend their apprentice course, run concurrently with the PJ Apprentice course.
I only tell you that to say; if a CRO were to somehow get selected from CROAS, commission, report to Kirtland AFB (apprentice courses) and then fail out of the course (I have never even heard of that happening), then I assume he would be at the needs of the Air Force for where he goes next. That's honestly a guess, like I said, I don't think it's ever happened.
Short answer- no, PJs going CRO don't go through the entire pipeline over again, they attend CRO specific SERE courses and the CRO Apprentice course, and they're selected and guaranteed to be a CRO (as long as they don't fail out of the course at some point).
For more information on both career fields, check out How To Be A PJ on all social (Instagram, FB, web site).
Hope I helped.