I won't go into it in much detail, but specifically for cave diving I don't believe it's a wise idea to have your first experience diving oc in a cave be as you bailout. There are nuances to cave diving that vary slightly between oc and ccr. I was cave certified for almost 10 years before I went to ccr cave. I'm very glad I didn't start as a ccr cave diver. I've been helitrox certified for a while and plan to move to full trimix soon (only held off due to having a pfo). Rather than learning on the ccr, I'm taking oc trimix (tech 1) because I and most of my mentors believe in both tech and cave diving you need to hone your skills first on OC. But those are just my opinions based on my experience. I will leave it up to any instructors who want to wade into the waters of that discussion. I think in N. Fl you will find 90+% of instructors would tell a student to go OC first.
When I did my original rEvo training, I asked my instructor (who is also a cave diver) this question. I.e. do I need to do OC Cave first, before going CCR Cave? Her answer was "once you're diving a rebreather, why would you EVER go INTO a cave on OC?"
More recently, I have been starting to prepare myself for cave training. I currently do not even have Cavern training. I have spoken with Joe Citelli and Mel Clark. They both have no problem taking me on as a student for CCR Cave, even though I have no OC cave training. I'm not saying either one of them would take just any CCR diver as a Cave student without OC Cave experience. I believe for both of them, it depends on their assessment of the individual. But, it seems clear (to me, anyway) that the subject is not as cut-and-dried as "you have to do OC Cave first."
I do not at all mean this is as some back-handed way of patting myself on the back when I say that I think a diver can develop very good OC buoyancy without going through an OC Cave class. I mean that generally. There are plenty of OC tech divers with excellent buoyancy and trim that have not taken a cave class. So, why should OC Cave be REQUIRED as a prerequisite?
I think your statement that 90% of instructors would tell a student to go OC first may possibly be exaggerated. Maybe that is 90% of the instructors in your personal circle?
One instructor I talked to basically said "as a CCR cave diver, you don't need as good OC buoyancy as you would if you were an OC cave diver. If you have to bail to OC in a cave, then it's an emergency and you are just getting out. You're not trying to run a reel, etc.." You are not doing the things that test your buoyancy like you would be if you were an OC cave diver.
I don't take any of that to mean that you could pass a CCR Cave class with **** OC buoyancy. I assume a CCR Cave class would include doing at least one BO OC exit. And that you would have to demonstrate ADEQUATE OC buoyancy during that exercise in order to pass the class. It just seems to me that your OC buoyancy does not have to be AS top notch as it needs to be for an OC Cave diver.